Evaluation of the potential of Lotus root (Nelumbo nucifera) flour as a fat mimetic in biscuits with improved functional and nutritional properties

ABSTRACT

In the present study, an effort was made to incorporate lotus (Nelumbo nucifera) as a fat mimetic for the development of functional biscuits. Functional properties, dough rheology, pasting profile, the microstructure of dough, antioxidant activities, physical, nutritional and sensorial properties of the samples were investigated. The addition of lotus root flour (LRF) resulted in a significant increase (P ≤ 0.05) in water absorption (57.51–72.40%) and dough stability time (7.38–13.10 min), while breakdown (802–554cP) and, setback viscosities (1154–900cP) decreased. Gluten content also decreased with the increased concentration of LRF, hence suggested weaker gluten network, which was further confirmed by scanning electron microscopic images (SEMIs) of biscuits dough. The total phenolic content (17.73–131.37 mg/mL and 14.43–94.67 mg/mL), DPPH radical scavenging activity-IC₅₀ (477.10 − 153.32 mg/mL and 500.41–94.32 mg/mL), and ferric reducing antioxidant power-IC₅₀ (348.21–53.62 mg/mL and 350.31–36.32 mg/mL) increased upon increasing the content of LRF in wheat flour and biscuits samples. Nutritional data revealed that protein (11.20–13.40%), ash (0.53–2.86%), and the crude fiber content (0.21–15.60%) of biscuits increased, and calories reduced (497–375kcal/100 gm). Therefore, this study explores the potential of using LRF as a fat mimetic in biscuits with the application on a commercial scale to enhance antioxidant, physical, nutritional, and sensory attributes.

RESUMEN

El presente estudio se propuso incorporar el loto (Nelumbo nucifera) como mimético de la grasa en el desarrollo de galletas funcionales. Con este propósito se investigaron las propiedades funcionales, la reología de la masa, el perfil de pegado, la microestructura de la masa, las actividades antioxidantes y las propiedades físicas, nutricionales y sensoriales de las muestras. La adición de harina de raíz de loto (LRF) produjo un aumento significativo (P≤0.05) de la absorción de agua (57.51-72.40%) y del tiempo de estabilidad de la masa (7.38-13.10min), al tiempo que disminuyeron las viscosidades de descomposición (802-554cP) y de retroceso (1,154-900cP). Por otra parte, con el aumento de la concentración de LRF también disminuyó el contenido de gluten lo que parece indicar la presencia de una red de gluten más débil. Esto se confirmó a partir de imágenes generadas con microscopio electrónico de barrido (SEMI) aplicado a la masa de las galletas. El contenido fenólico total (17.73-131.37 mg/mL y 14.43-94.67 mg/mL), la actividad de eliminación de radicales de DPPH-IC₅₀ (477.10-153.32 mg/mL y 500.41-94.32 mg/mL) y el poder antioxidante reductor de hierro-IC₅₀ (348.21-53.62 mg/mL y 350.31-36.32 mg/mL) se incrementaron cuando se elevó el contenido de LRF en las muestras de harina de trigo y en las galletas. Los datos nutricionales dan cuenta de que la proteína (11.20-13.40%), la ceniza (0.53-2.86%) y el contenido de fibra cruda (0.21-15.60%) de las galletas aumentaron, mientras que las calorías se redujeron (497-375 kcal/100gm). Por lo tanto, este estudio explora el potencial que conlleva usar la LRF para mimetizar la grasa en galletas con su aplicación a escala comercial de manera de mejorar los atributos antioxidantes, físicos, nutricionales y sensoriales.

KEYWORDS:

• Biscuit
• lotus root flour
• dough rheology
• antioxidant activity
• scanning electron microscopy
• texture
• sensory properties

PALABRAS CLAVE:

• Galleta
• harina de raíz de loto
• reología de la masa
• actividad antioxidante
• microscopía electrónica de barrido
• textura
• propiedades sensoriales

1. Introduction

The adverse effect of excessive dietary fat consumption is virtually universal, and numerous chronic diseases are linked to high fat intake, among them coronary heart diseases (CHD) are listed on top. Several studies have indicated that the high postprandial serum triglyceride (TAG) concentration is a leading risk factor and is related to high fat intake, particularly saturated fat (Mickova et al., 2007). The serum TAG peak is raised during 2–6 hours of meal intake and indicates the long frequency in eating habits. Furthermore, eating habits with a high amount of fat content is one of the primary causes of nutrition-related obesity and overweight disorders, which are directly linked with numerous non-communicable chronic diseases (NCDs), including CHD. Therefore, the low-fat diet has become essential among health-conscious peoples and a challenge for the industrialists to meet the consumer’s demand (Zoulias et al., 2002).

One of the alternatives to reduce calories in the diet is to replace the dietary fat by non-caloric or low caloric food ingredients, i.e., the fat substitutes or fat mimetics. A fat replacer is a substance that induces partially or fully all the functions of fat, providing ‘no’ or ‘low’ calories to the food products. Moreover, obesity, CHD, and TAG levels may be reduced by inducing fat replacers in food products (Miraglio, 1995).

Fat replacers or fat mimetics are may be carbohydrate, protein, and fiber-based. A variety of fat replacers are available, such as the modified starches, celluloses, cellulose derivatives, microcrystalline cellulose, gelatin, pectin, gums, dietary fibers, micro-particulate proteins and, etc.(Frye & Setser, 1993). However, all of them perform similar functions as fat in a food system (Corliss, 1992; Yackel & Cox., 1992). The functions of fat mimetics in a food system include diverse type activities, such as they provide flavor, palatability, tenderness, creaminess, viscosity, opacity, lubricity, resistance to other than fat-molecular interactions, ingredients coating, etc. (Lucca & Tepper, 1994). Some of these properties of fat mimetics are responsible for weak gluten network, which is desirable in biscuits manufacturing. The unique function of the fat is to impart flavor; however, fat mimetics do not provide flavor similar to fat and generally have more excellent water absorption. Therefore, emulsifiers are required in case of the incorporation of lipophilic flavor in the product (Akoh, 1998). The high caloric density of fat (9 kcal/g) develops satiety in foods, the feeling of satiety is achieved by the diet rich in fibers as fibers have the ability to absorb the excess of water and swells, providing a sense of fullness after the meal which is considered as one of the attributes of fibers to mimic fat.

Bakery items are known as high fat products which are frequently consumed by people of almost all age groups (Rodríguez‐García et al., 2012). Hence, there is a need to develop such baked products that have fat substitution to reduce the caloric value but with minimum or no impact on the final edible quality of the product. Lotus (Nelumbo nucifera) is a rhizomatous aquatic, non-conventional, and is a very common vegetable in the diets of Chines, Indians, Japanese, and Australians. Lotus is also found in Pakistan, especially in the upper part of Sindh and lower areas of Punjab. Different parts of the lotus plant, including root, stem, and leaves that have been used for edible purposes (Shad et al., 2011).

Polysaccharides like gums, starches, pectin, and cellulose are capable of binding water and, therefore, can serve as thickeners or gelling agents and therefore as fat replacers in foods in view of the fact that high viscosity and gel formation are the desired properties in a fat substitute (Yemenicioglu et al., 2019). Some of the components of lotus root possess functional properties such as the aqueous solubility, swelling, water binding, foaming, gelation, and emulsifying capacity (Shad et al., 2011) which could make it a good fat mimetic in food products. Moreover, variety of the components of the lotus root exhibit multiple nutritional and medicinal benefits. It is a good source of dietary fibers, proteins, and sugars (Sridhar & Bhat, 2007). The main antioxidative phytonutrients identified in lotus root are phenolics, including catechol, gallic acid, catechins, and epicatechins, etc. (Hu & Skibsted, 2002).

Some of the commonly used fat replacers in food systems on commercial scale include inulin, polydextrose, galacto-oligosacchrides, cocoa butter, etc. Inulin is a hydrophilic fructose polymer, and so a carbohydrate derived fat replacer that performs functions as dietary fiber, bulking agent, and as a prebiotic so nutritionally inulin is a superior alternative. Numerous studies based on the utilization of dietary fibers or inulin as a fat replacer in biscuits have been reported (Rodríguez‐García et al., 2012). Seker et al. (2010) depicted that apricot kernel flour at level of 10% and 20% could be used as a suitable replacer of fat in cookies. Furthermore, Sudha et al. (2007) reported fat replacement in biscuits by incorporation of polydextrose, maltodextrins, and simplesse. Polydextrose is gluco-oligosacchrieds that is resistant to digestion and is also known to replace butter in many dairy foods, especially in bakery products (Mickova et al., 2007).

Biscuits have always been one of the most traditional bakery products rich in fat content. Since there is no comprehensive information available in the literature for the utilization of lotus root flour (LRF) as fat mimetic in biscuits, the present study was designed to investigate the effect of LRF addition on the rheological, nutritional, nutraceutical, and sensory properties of the dough and biscuits. The results after a successful comprehensive study suggest its use at the industrial level to enhance the utilization of LRF for the development of fat replaced baked products that may be more economical, practical, and nutritious.

2. Materials and methods

2.1. Collection of raw materials

Commercial wheat flour was provided by Graib Sons Private Limited, Karachi and egg, salt and icing sugar were purchased from the local market of Karachi. Partially saturated fat (shortening) was obtained from Paracha Mills Ghee Textile Unit, Karachi. The Sulop Chemicals, Karachi, provided glucose and soy lecithin.

2.2. Chemicals

All chemicals used for the study were analytical reagent grade. Sodium dihydrogen phosphate, sodium monohydrogen phosphate, trichloroacetic acid, methanol, and folin-ciocalteau reagent were procured from Dae-Jung Chemicals, South Korea. Ferric chloride, potassium ferrocyanide, gallic acid, catechin and 2,2-diphenyl-1-picryl-hydrazyl (DPPH) were obtained from Sigma-Aldrich, Germany.

2.3. Preparation of lotus root flour

Lotus roots (LRs) were locally selected for the present study. LRs were thoroughly washed with distilled water to remove impurities from the surface, then peeled and washed again by distilled water. Lotus root was manually cut into thin slices of thickness 0.002 cm and dried in a hot air oven (DSO-300 D, digisystem laboratory instruments, Taiwan) at 60°C for 8 h. Dried lotus root flakes were milled by laboratory hammer miller (3100, Perten Instruments) and then passed through the sieve of 420 µm. The fine lotus root flour (LRF) was stored in airtight glass bottles at 4°C. Varying concentrations of LRF [5, 10, 15, 20, and 25% (w/w)] were added to wheat flour as a fat mimetic to have sample flours of varying wheat to LRF ratios, represented as LRF-WF.

2.4. Physicochemical analysis

Proximate profiles of LRF-WF blends were analyzed according to the method of Ali et al. (2018). Moisture was determined by moisture analyzer (Brabender 51–55, CW Brabender, Duisbury, NJ, USA). Protein and ash contents were estimated by Brabender Kernelyzer (Brains Instruments, Germany). Fat content was estimated by AACC Method 30–25 (AACC, 1999). Carbohydrate content was calculated by subtracting the contents of protein, fat, ash, and moisture from 100. Dry gluten (DG) and gluten index (GI), were estimated by Glutomatic (2200, Perten Instruments). Each sample was tested in triplicates for proximate analysis.

2.5. Dough rheological properties

The effect of the incorporation of LRF in wheat flour in various concentrations on rheological properties was studied by the AACC Method 54–21(AACC, 1999) using Frainograph (mixer bowl 300 g, Brabender OHG, Duisburg, Germany). The parameters measured include water absorption (WA), dough development time (DDT), the degree of softening (DoS), dough stability time (DST), and farinograph quality number (FQN).

2.6. Pasting properties of flour

The pasting properties of flour were determined according to the AACC Method 22–10 (AACC, 1999) by using the Microvisco-Amylo-Graph (Brabender, Duisburg, Germany). Distilled water (100 mL) was added to 15 g of flour and the slurry was heated at 50°C with constant stirring at 160 rpm for 10 s. The mixture was later held at 50°C for 1 min and was heated at 95°C for 7.3 min. The slurry was held at 95°C for 5 min (holding time/pasting strength) and finally cooled at 50°C for 7.7 min. The parameters measured for each sample include the average values for the beginning of gelatinization, maximum viscosity, breakdown, and setback viscosities.

2.7. Functional properties

Water absorption capacity (WAC) and oil absorption capacity (OAC) of wheat flour and LRF were determined according to the method of Ahn et al. (2005). Briefly, the WAC was determined by taking 1 gm of the flour sample in a 20 ml centrifuge, and 10 mL of distilled water was added to it; the mixture was vortexed for 2 min. The tube was centrifuged at 2200 × g for about 20 min and the supernatant was decanted while the residual pellets were weighed and analyzed for WAC. The same procedure was used to determine OAC using 10 mL soya bean oil.

2.8. Micromorphology of biscuits dough

The microstructure of biscuits dough was evaluated by scanning electron microscope (JEOL, Analysis system, Model # JSM-6380, Japan) as described by Ali et al. (2018). Briefly, the samples were first frozen at −20°C, then transferred into the freeze dryer (Laboratory Freeze Dryer VaCo 2, Germenay), which operated at −50°C and 0.1 m Pa. Freeze-dried dough samples were cut transversally into slices with a sharp blade without damaging the structure. Samples were mounted on the sample holder and sputter-coated with gold (2 min, 2 mbar). Scanning electron microscopic (SEM) studies were carried out on an applied voltage of 15 KV at 500X magnification.

2.9. Biscuits preparation

The formulations of biscuits samples are presented in Table 1. The fat replaced biscuits were prepared using the same recipe as mentioned for control except that the fat was replaced by lotus root flour (LRF) at the concentrations of 5, 10, 15, 20, and 25% (w/w). Biscuit samples were prepared, as reported by Ali et al. (2018). Briefly describing the dough was sheeted at a fixed thickness of 7.2 mm and was cut into circular shapes using a biscuit cutter having a fixed diameter of 36.3 mm. Biscuits were baked at 180°C for 15 min in an oven. About 25 biscuits were baked per batch, and each batch was prepared in triplicates.

Table 1. Composition of biscuits.

Tabla 1. Composición de las galletas.

	Level of fat replacement
Ingredients (g/100 g)	Control	5% LRF	10% LRF	15% LRF	20% LRF	25% LRF
Allpurpose wheat lour (g)	100	100	100	100	100	100
Fat (g)	40	38	36	34	32	30
Icing Sugar(g)	40	40	40	40	40	40
Baking powder (g)	02	02	02	02	02	02
Egg (g)	13.4	13.4	13.4	13.4	13.4	13.4
Soya lecithin (g)	0.25	0.25	0.25	0.25	0.25	0.25
Salt (g)	01	01	01	01	01	01
Glucose (g)	0.5	0.5	0.5	0.5	0.5	0.5
Water (mL)	20 ± 5	20 ± 5	20 ± 5	20 ± 5	20 ± 5	20 ± 5
LRF (g)	-	02	04	06	08	10

2.10. Antioxidant properties and polyphenolics

Antioxidant activity of LRF-WF blends, LRF-WF biscuits, and control biscuits was determined by free radical scavenging activity and ferric reducing power. Extracts of LRF-WF blends, control, and LRF-WF biscuit samples were prepared by the method of Fan et al. (2007). The blends of LRF-WF and biscuits powder (control and LRF-WF) was added to 80% acetone at the concentration of 60 mg/mL, 125 mg/mL, 185 mg/mL and 250 mg/mL and the mixtures were analyzed as described by Fan et al. (2007).

2.11. Total phenolic content

Total phenolic content (TPC) of samples were determined by using Folin–Ciocalteu reagent, as described by Salar and Purewal (2017). The absorbance of the extracts was recorded at 765 nm against a blank, and the results were expressed as mg Gallic acid equivalent/100 g (mg GAE/100 g) of the extract on dry weight (DW) basis obtained from the standard calibration curve.

2.12. 2,2-diphenyl-1-picrylhydrazyl-DPPH radical scavenging activity

The antioxidant activity of the extracts of LRF-WF blends, and of the extracts of the biscuits samples was determined by using the technique of Fan et al. (2012) with slight modification. The DPPH solution was prepared by dissolving DPPH (33.9 mg) in 100 mL methanol. The 1 mL sample of different concentrations as 60 mg/mL, 125 mg/mL, 185 mg/mL, and 250 mg/mL, were mixed with 1 mL of DPPH solution separately and placed in the dark for about 30 min. The absorbance values were recorded at the wavelength of 517 nm using a spectrophotometer (Perkin Elmer, Lambda 25, and UV-Vis Spectrophotometer). The scavenging activity calculated as follows.

Scavenging activity % = Absorbance of control – Absorbance of sample/Absorbance of control×100

2.13. Ferric/Ferricyanide (Fe³⁺) reducing antioxidant power

Ferric/Ferricyanide reducing antioxidant power (FRAP) values of the samples were analyzed according to the method of Oyaizu (1986) with slight modification adapted by Gawlik-Dziki et al. (2014). Perl’s Prussian color was measured at an absorbance of 700 nm, where the increase in absorbance is an indication of increased antioxidant activity (Gulcin et al., 2004).

2.14. Color analysis

The color was measured using an NH300 Portable Colorimeter according to the method of Ohizua et al. (2017). Color values L*, a*, and b* were recorded where each value is the average of four measurements at different points of the biscuits. L* value is the lightness variable from 100 for perfect white to zero for black. In contrast, a* and b* values are the chromaticity values that indicate (+) redness/(-) greenness and (+) yellowness/(-) blueness respectively.

2.15. Textural analysis

Biscuits samples were determined for their breaking strength (hardness) using texture analyzer, (UTM, Zwick/Roell, Germany) as described by Kuchtova et al. (2018) utilizing three points bend rig technique (Load cell: 5 kg, pre-test speed: 1.0 mm/s, test speed: 5.0 mm/s, post-test speed: 10.0 mm/s, distance: 10 mm, trigger force: 50 N). Measurements of each biscuits samples were done in triplicates. The textural measurements were done in triplicates.

2.16. Dimensional analysis

The diameter or the width of biscuits was measured twice by rotating the biscuit at 90°C. The thickness of biscuits was measured by stacking three biscuits on top of one another, and the total height measurement was divided by three to get the average value. The spread ratio of biscuits was calculated from the fraction of diameter and thickness (Kohajdová et al., 2014).

2.17. Nutritional analysis

Nutritional analysis of control and LRF-WF biscuits included the analyses of protein, fat, carbohydrate, ash, moisture, crude fiber, and kilocalories. Protein and ash contents were determined by the Kjeldahl apparatus (Thermo Fisher Scientific) and Muffle furnace (Thermo Fisher Scientific), respectively, according to AACC Methods 08–01 and 46–10, respectively, (AACC, 1999). Fat content and crude fiber were determined by the Soxhlet apparatus (Thermo Fisher Scientific) and Fiber digester (Marconi, MA-444, Brazil), respectively, by using AACC Methods 30–25 and 32–10, respectively, (AACC, 1999). Moisture content was determined by moisture analyzer (Brabender 51–55, CW Brabender, Duisbury, NJ, USA). The total carbohydrate was determined by difference: Carbohydrate = 100 − (% moisture + % protein + % fat + % ash + % crude fiber). Calories were measured by applying the Atwater general factor system: carbohydrate (4 Kcal/g), lipid (9 Kcal/g), and protein (4 Kcal/g).

2.18. Sensory evaluation

Sensory examination was carried out in the baking laboratory following the method of Ali et al. (2018). Biscuits samples were evaluated by 40 trained panelists male and female (ages 24–45) comprised mainly of students and staff members of the Department of Food Science and Technology, University of Karachi (Karachi, Pakistan). The panelists were trained by utilizing the sensory profiles method (Lawless & Heymann, 2010) with the commercial biscuits and prototypes prepared in the baking laboratory. By means of this training, a specific terminology for the sensory characteristics and ranges for each attribute was agreed upon. The trained sensory panel passed the basic taste test, the odor test, and the color vision test, and their evaluation capacity were routinely verified by way of individual control cards. Panelists used 9 points hedonic scale (1 = extremely dislike to 9 = extremely like) for analyzing the desirability of biscuit samples for taste, color, appearance, texture, and overall acceptability. The characterization of the products was carried out under daylight and in portable cabins within the sensory laboratory. The ration of consumption was one whole biscuit of each reference, maintained at a temperature of 25°C. Water was served to the evaluators for cleaning of the mouth between the different samples. The samples were judged without replication. With the aim of testing the reliability of the results, the control biscuit was introduced two times in the evaluations, randomly between other samples.

2.19. Statistical analysis

All the analyses were performed in triplicate, and the average value was calculated. The results were expressed as mean ± standard deviation. The data were analyzed by analysis of variance (ANOVA) using SPSS (Version 17.0. Inc., Chicago, USA) statistical program. Duncan’s multiple range tests were applied to identify any significant differences among the treatments at P ≤ 0.05.

3. Results and discussion

3.1. Physicochemical properties

The increased concentration of lotus root flour (LRF) in wheat flour resulted in increased, protein, crude fiber, and ash contents in view of the richness of LRF flour in these ingredients. The moisture content of the samples ranged from 13.81 to 14.20% with 100% wheat flour having the highest value. The lower values of LRF-WF blends is advantageous because it will reduce the proliferation of spoilage organisms, especially mold, thus, improving the shelf stability of the product (Ocheme et al., 2018). The protein content of LRF-WF blends increased from 10.80 to 11.70%, and ash content increased from 0.62 to 1.07%, while fat content of flour blends was not significantly different (P ≤ 0.05). Carbohydrate content of flour blends ranged from 71.83 to 73.02%. Generally, vegetable flour has been incorporated in numerous food products for better nutritional profile and functionality than products solely made from wheat flour (Ocheme et al., 2018). Furthermore, the addition of LRF reduced the dry gluten content and gluten index (GI) of flour blends.

3.2. Water absorption and oil absorption capacity

The texture, mouthfeel, and yield of the product were determined by calculating water absorption capacity (WAC) and oil absorption capacity (OAC) (Zhang et al., 2007). Table 3 represented WAC of flour samples that ranged from 146 to 162%. Among the flour blends, the highest WAC was observed for 25% LRF (162%), followed by 20% LRF (155.43%) and lowest for control (146%). Results suggested that the addition of LRF to wheat flour influenced the amount of water absorption. Higher WAC might be due to the presence of high fiber, protein, and carbohydrate contents of LRF-WF blends (Kaur & Singh, 2007). Complex carbohydrates, including plant fibers, have proved themselves as successful fat replacers due to their ability to bind water and producing a paste which can mimic the texture and mobility of fats in food system by providing lubrication to enhance viscosity and flow properties similar to fat (Patel et al., 2020). The high amount of water absorption is due to the presence of more numbers of hydroxyl groups in dietary fibers which enhances the rate of interaction of OH groups (Mironeasa et al., 2019). Adebowale et al. (2012) also reported an increase in WAC of sorghum composite flour consisting in biscuits formulation.

Table 2. Effect of Lotus root flour (LRF) addition on proximate and chemical properties of wheat flour.

Tabla 2. Efecto de la adición de harina de raíz de loto (LRF) en las propiedades químicas y aproximadas de la harina de trigo.

Sample	Moisture (%)	Protein (%)	Ash (%)	Fat (%)	Carbohydrate (%)	Gluten Index		Dry gluten (%)
Wheat flour (control)	14.20 ± 0.01^a	10.80 ± 0.05^d	0.62 ± 0.00 ^f	1.36 ± 0.01^a	73.02 ± 0.68^e	94.01 ± 0.56^a	7.60 ± 0.07^a
5% LRF	14.00 ± 0.05^b	11.30 ± 0.02 ^c	0.74 ± 0.01^e	1.36 ± 0.02^a	72.60 ± 0.62^e,d,e	93.11 ± 0.99^a,b	6.80 ± 0.15^b
10% LRF	13.90 ± 0.01^b,c	11.51 ± 0.02^b	0.86 ± 0.01^d	1.37 ± 0.01^a	72.36 ± 0.46 ^c	90.10 ± 0.90^d	6.80 ± 0.05^b
15% LRF	13.81 ± 0.07 ^c	11.61 ± 0.04^a	0.93 ± 0.02 ^c	1.37 ± 0.01^a	72.28 ± 0.41 ^c	93.12 ± 0.49^a,b	6.40 ± 0.05 ^c
20% LRF	13.90 ± 0.02^b,c	11.70 ± 0.10^a	1.02 ± 0.02^b	1.36 ± 0.02^a	72.02 ± 0.36^b	91.01 ± 0.65 ^c,d	6.80 ± 0.25^b
25% LRF	14.00 ± 0.10^b	11.70 ± 0.03^a	1.10 ± 0.01^a	1.37 ± 0.02^a	71.83 ± 0.31^a,b	92.13 ± 0.75^b,c	6.20 ± 0.05 ^c

^{a, b, c d}Means within a column differ significantly (P ≤ 0.05) and calculated by the Duncan method. Each value expressed as mean ± SD (n = 3).

^{a, b, c d}Las medias dentro de una columna difieren significativamente (P ≤ 0.05) y se calculan por el método Duncan. Cada valor se expresa como media ± DE (n = 3).

Table 3. Effect of different levels of lotus root flour (LRF) on functional properties of wheat flour.

Tabla 3. Efecto de diferentes niveles de harina de raíz de loto (LRF) en las propiedades funcionales de la harina de trigo.

Sample	Water absorption capacity (%)	Oil absorption capacity (%)
Wheat flour (control)	145.60 ± 1.01^a	153.17 ± 2.10 ^f
5% LRF	146.31 ± 1.02^b	152.22 ± 1.03^e
10% LRF	146.96 ± 1.01^b	150.21 ± 2.11^d
15% LRF	148.60 ± 1.05 ^c	149.71 ± 1.07 ^c
20% LRF	150.26 ± 2.03^d	146.82 ± 2.01^b
25% LRF	155.40 ± 1.04^e	140.30 ± 1.00^a

^{a, b, c, d, e, f}Means within a column differ significantly (P ≤ 0.05) and calculated by Duncan method. Each value expressed as mean ± SD (n = 3).

^{a, b, c, d, e, f}Las medias dentro de una columna difieren significativamente (P ≤ 0.05) y se calculan por el método Duncan. Cada valor se expresa como media ± DE (n = 3).

In bakery products, fat absorption is desired as it contributes to improvement in palatability, flavor, and its retention. Moreover, saturated fat is beneficial in the extension of shelf life as compared to unsaturated fractions of fats because they are readily prone to oxidative rancidity, hence reduce the shelf life of the product (Chandra et al., 2015). OAC of flour blends decreased with the increase in the concentration of LRF (from 150 to 140%), whereas, wheat flour (control) showed maximum OAC (153.03%) (Table 2). Similarly, Klunklin and Savage (2018) also reported decrease OAC for wheat-purple rice flour. Protein in flour contains both hydrophobic and hydrophilic groups, which are responsible for oil and water absorption simultaneously (Wani et al., 2013). However, in this study, the incorporation of LRF decreased the OAC, which is attributed due to protein consist of more hydrophilic content.

3.3. Pasting properties of flour

The addition of LRF in refined wheat flour significantly (P ≤ 0.05) changed the pasting behavior of flour samples (Table 4). The temperature of gelatinization provides an estimate of the minimum cooking temperature desired. The pasting temperature of wheat flour and LRF-WF blends (67.3–67.5°C) did not change significantly (P ≤ 0.05), which suggested that starch granules present in wheat flour and LEF-WF blends swell at the same temperature. Incorporation of LRF in wheat flour significantly (P ≤ 0.05) decreased the maximum viscosity from 2304 to 1702 cP. The decrease in viscosity might be due to the high WAC of LRF as compared to wheat flour, which ultimately resulted in the development of weak gluten network and therefore decreases the viscosity (Igbabul et al., 2014). Breakdown and setback viscosities also decreased from 802 to 554 cP and 1154 to 900 cP, respectively, with increased concentration of LRF. The decreased breakdown viscosity seems to be correlated to the increased significant water holding strength of fibers and other hydrophilic biopolymers. It is responsible for the longer baking time that ultimately resulted in enhanced deep color and hard texture of biscuits samples (Ali et al., 2018). Furthermore, the lesser value of setback demonstrated a lower degree of retrogradation of a starch paste (Varavinit et al., 2003). Results suggested that adding LRF could significantly (P ≤ 0.05) inhibit the retrogradation of the gelatinized flour sample due to the presence of phenolic components which may interact – OH groups of amylose chain and do not allow amylose molecules to arrange themselves together (Fu et al., 2015).

Table 4. Micro Visco-Amylo-Graph properties of wheat flour and different ratios of lotus root flour (LRF) incorporated.

Tabla 4. Propiedades micro-visco-amilográficas de la harina de trigo y diferentes proporciones de harina de raíz de loto (LRF) incorporadas.

Sample	Beginning of gelatinization (cP)	Gelatinization temperature (°C)	Maximum viscosity (cP)	Breakdown viscosity (cP)	Setback viscosity (cP)
Wheat flour (control)	44.10 ± 1.01^b	67.53 ± 2.01^a	2304.04 ± 6.01^a	802.11 ± 4.01^a	1154 ± 6.82^a
5% LRF	54.14 ± 1.50^a	67.54 ± 3.61^a	2286.07 ± 10.01^a	764.05 ± 1.80^b	1002 ± 2.70^b
10% LRF	58.11 ± 1.70^a	67.56 ± 1.01^a	2268.02 ± 7.10^a	734.07 ± 3.70 ^c	964 ± 4.41 ^c
15% LRF	40.21 ± 0.51 ^c	67.57 ± 2.65^a	2216.03 ± 10.11^b	694.01 ± 2.62^d	958 ± 2.13 ^c
20% LRF	48.13 ± 1.20^b	67.60 ± 3.10^a	2204.08 ± 7.01^b	676.01 ± 2.91^e	926 ± 3.21^d
25% LRF	42.12 ± 0.40 ^c	67.56 ± 3.61^a	1702.01 ± 14.06 ^c	554.06 ± 4.52 ^f	900 ± 4.50^e

^{a, b, c, d, e, f}Means within a column differ significantly (P ≤ 0.05) and calculated by the Duncan method. Each value expressed as mean ± SD (n = 3).

^{a, b, c, d, e, f}Las medias dentro de una columna difieren significativamente (P ≤ 0.05) y se calculan por el método Duncan. Cada valor se expresa como media ± DE (n = 3).

3.4. Rheological properties of dough

There was a continuous increment in water absorption (WA) (63.6 to 72.4%) and dough stability time (DST) (8.6 to 13.1 min) with gradual addition of LRF (Table 5). Increased WA was probably due to the presence of hydrophilic components such as the polysaccharides, the major components of dietary fibers in LRF that facilitate water-binding activity (Ahmad et al., 2015). Dough development time (DDT) also increased with the inclusion of LRF in wheat flour. The increase in DDT may be attributed to the increase in protein content and ash responsible for the rise in WA of the dough. Furthermore, Ahmad et al. (2015) also reported the increased WA and DDT upon the incorporation of green tea powder in wheat flour. The higher WA values, as previously reported, also are likely due to higher number of hydroxyl groups present in hydrophilic components such as polyphenols and polysaccharides present in tea (Ahmad et al., 2015). It confirms our observations as LRF is an excellent source of polyphenols and polysaccharides reported earlier as well (Hu & Skibsted, 2002; Sridhar & Bhat, 2007). In general, high WA improves the baking performance due to greater hydration of flour components and helping dough development during mixing (Md Zaidul et al., 2004) while wheat flour showed lower DDT and higher DST than the LRF-WF blends. Inconsistency in the mixing properties of the flour sample was attributed to an increase in fiber and protein content (Bae et al., 2014). Moreover, the increased farinograph quality number (FQN), responsible for the dough strength and in DDT and DST (Ali et al., 2018).

Table 5. Farinograph properties of wheat flour and different ratios of louts root flour (LRF) incorporated.

Tabla 5. Propiedades farinográficas de la harina de trigo y diferentes ratios de harina de raíz de loto (LRF) incorporadas.

Sample	Water absorption (%)	Dough development time (min)	Dough stability time (min)	Farinograph quality number
Wheat flour (control)	57.51 ± 0.2^a	2.07 ± 0.01^a	7.38 ± 0.18^a	86 ± 1.02^b
5% LRF	63.60 ± 0.20^b	5.90 ± 0.12^b	8.60 ± 0.1^a	77 ± 1.09^a
10% LRF	64.50 ± 0.33 ^c	7.80 ± 0.24 ^c	8.80 ± 0.4^b	120 ± 2.24 ^c
15% LRF	64.90 ± 0.51 ^c	7.80 ± 0.22 ^c	9.60 ± 0.2^c	120 ± 2.01 ^c
20% LRF	65.80 ± 0.58^d	8.10-±0.16^d	10.20 ± 0.33^d	127 ± 1.04^d
25% LRF	72.40 ± 0.81^e	11.50 ± 0.14^e	13.10 ± 0.40^e	139 ± 2.02^e

^{a, b, c, d, e}Means with different letters in superscript within a column differ significantly (P ≤ 0.05) and calculated by Duncan method, each value expressed as mean ± SD (n = 3).

^{a, b, c, d, e}Las medias dentro de una columna difieren significativamente (P ≤ 0.05) y se calculan por el método Duncan. Cada valor se expresa como media ± DE (n = 3).

3.5. Scanning electron microscopy of biscuits dough

The micrograph of control biscuit dough showed small and large intact starch granules which were uniformly distributed along with the gluten matrix (Figure 1(a)). However, as indicated in Figure 1(b) the substitution of 5% LRF facilitates the starch granules to be partially trapped in the protein matrix. Furthermore, LRF particles were also visualized adhering to starch granules and protein fibrils randomly. It was observed that the protein matrix uniformly coated the starch granules (Figure 1(c)). However, as the concentration of LRF increased beyond 10%, the gluten matrix was disrupted, and starch granules embedded within the broken protein matrix initiate in the development of intercellular spaces, as observed in Figure 1(d-f). The literature revealed that even though microstructural properties of fat mimetics are quite different from fat when they are used to replace fat in food products, the end products show comparable qualities to the standard that is in agreement with our observations (Patel et al., 2020).

Figure 1. Scanning electron microscopic images at 500 X of biscuit dough (a) Control (biscuits dough without fat replacement), (b) 5% lotus root flour, (c)10% lotus root flour, (d) 15% lotus root flour, (e) 20% lotus root flour, (f) 25% lotus rot flour.

Figura 1. Imágenes de microscopía electrónica de barrido a 500 X de la masa de galletas (a) Control (masa de galletas sin remplazo de grasa), (b) 5% de harina de raíz de loto, (c) 10% de harina de raíz de loto, (d) 15% de harina de raíz de loto, (e) 20% de harina de raíz de loto, (f) 25% de harina de raíz de loto.

3.6. Antioxidant and polyphenolics analysis

Increasing the concentration of LRF in the wheat flour increased the DPPH radical scavenging activity significantly (P ≤ 0.05) as compared to control, i.e., decrease the IC₅₀ values (Table 6). Increased scavenging activity of LRF-WF blends is associated with the presence of radical scavengers or oxidative inhibitors in LRF. Besides, the baking process generated the brown-colored pigments called melanoidins. These brown-colored melanoidins pigments were found to be responsible for further increase in the antioxidant potential of the product (Sharma et al., 2012). Similar results were reported by Jan et al. (2015) on varying the concentrations of buckwheat flours in wheat flour-based biscuits samples.

Table 6. Value of 2, 2- Diphenyl-1-picryl-hydrazyl (DPPH), radical scavenging activity, Ferric/Ferricyanide (Fe³⁺) reducing antioxidant power (FRAP) and total phenolic content (TPC) at different levels of lotus root flour (LRF) incorporated in wheat flour and biscuit samples.

Tabla 6. Valor de 2,2- difenil-1-picril-hidrazilo (DPPH), actividad de eliminación de radicales, Férrico/Ferrocianuro (Fe3+) poder antioxidante reductor (FRAP) y contenido fenólico total (TPC) en diferentes niveles de harina de raíz de loto (LRF) incorporada en muestras de harina de trigo y de galletas.

	Flour samples			Biscuit samples
Sample	DPPH- Scavenging activity- IC50 (mg/ml)	FRAP-IC50 (mg/ml)	TPC (mg GAE*/100 gm DW^1)	DPPH-Scavenging activity- IC50 (mg/ml)	FRAP- IC50 (mg/ml)	TPC (mg GAE*/100 g DW^1)
Wheat flour	477.10 ± 3.15^e	348.21 ± 4.52^e	17.73 ± 0.11^a	500.41 ± 3.15 ^f	350.31 ± 4.52 ^f	14.43 ± 0.12^a
5% LRF	321.40 ± 1.29^d	127.35 ± 0.51^d	21.64 ± 1.18^b	245.40 ± 1.29^e	104.45 ± 0.4^e	16.74 ± 2.18^b
10% LRF	248.62 ± 1.21 ^c	125.34 ± 0.21^d	52.81 ± 2.31 ^c	205.62 ± 1.21^d	79.64 ± 0.3^d	39.21 ± 2.21 ^c
15% LRF	227.04 ± 1.01^b	92.32 ± 0.45 ^c	90.69 ± 3.42^d	151.04 ± 1.01 ^c	65.39 ± 0.15 ^c	76.49 ± 3.12^d
20% LRF	210.60 ± 0.92^a	78.81 ± 0.13^b	118.37 ± 3.55^e	120.60 ± 0.92^b	49.88 ± 0.13^b	83.34 ± 3.15^e
25% LRF	153.32 ± 0.42 ^f	53.62 ± 0.11^a	131.37 ± 3.82 ^f	94.32 ± 0.10^a	36.32 ± 0.12^a	94.16 ± 3.92 ^f

^{a, b, c, d, e, f}Means in the column differ significantly and calculated by Duncan method (P ≤ 0.05). Each value expressed as mean ± SD (n = 3).

*GAE = Gallic acid equivalent

¹DW = dry weight

^{a, b, c, d, e, f}Las medias dentro de una columna difieren significativamente (P ≤ 0.05) y se calculan por el método Duncan. Cada valor se expresa como media ± DE (n = 3).

*GAE= Equivalente de ácido gálico

¹DW= peso seco

The maximum FRAP (25% LRF) was observed followed by 20% LRF (Table 6), while the control biscuit samples produced the highest IC₅₀ value, hence the lowest FRAP. The higher level of fat replacement in biscuits revealed a strong FRAP (i.e., lower IC₅₀ values). The baking process further improved the FRAP as lower IC₅₀ values were observed in biscuits as compared to LRF-WF samples, as reported in the case of DPPH. The incorporation of buckwheat flour in biscuits resulted in an increase in FRAP upon baking, as previously reported (Jan et al., 2015).

Despite a more significant decrease in total phenolic content (TPC) of LRF during baking as compared to LRF-WF blends, the TPC values in LRF-WF biscuits were still higher than that of control biscuits (Table 6). Biscuits prepared with 25% LRF showed the highest TPC, followed by 20% LRF and 15% LRF. A decrease in TPC of buckwheat flour observed when biscuits containing buckwheat flour were baked at 180°C (Jan et al., 2015). The reduction in TPC values generally is linked to oxidative damage or the oxidation of the phenolic compounds during baking (Sharma et al., 2012).

3.7. Evaluation of end quality attributes of biscuits

3.7.1. Dimensional characteristics

Dimensional characteristics of control and LRF-WF biscuits are presented in Table 7. The addition of LRF in biscuit samples significantly (P ≤ 0.05) affected thickness, diameter, and so the spread ratio. An increase in diameter was observed at a concentration of 5% LRF to 15% LRF. However, when the level increased beyond 15%, the diameter of biscuits decreased. LRF significantly (P ≤ 0.05) increased the thickness of biscuits samples. Spread ratio is one of the important physical attributes in evaluating the quality of biscuits (Kuchtova et al., 2018). The spread ratio increased up to 10% LRF and then declined. Similar findings of increased spread ratio in biscuits were also reported by Kuchtova et al. (2018). It seems that an increased amount of dietary fibers in LRF-WF biscuits could be the reason for increased thickness, reduced diameter, and decreased spread ratio when a higher amount of fat was replaced with LRF (Turksoy & Ozkaya, 2011).

Table 7. Effect of lotus root flour (LRF) on dimensional and textural properties of biscuits.

Tabla 7. Efecto de la harina de raíz de loto (LRF) en las propiedades dimensionales y de textura de las galletas.

Sample	Diameter^1 (cm)	Thickness^1 (cm)	Spread ratio^1	Breaking Strength^1 (N)
Control*	4.45 ± 0.12^b	0.89 ± 0.07 ^c	5.05 ± 0.47 ^c, d	18.51 ± 0.14^d
5% LRF	4.71 ± 0.10 ^c	0.77 ± 0.03^a	6.15 ± 0.35^e	12.36 ± 0.11^a
10% LRF	4.53 ± 0.16^b	0.87 ± 0.03^b	5.09 ± 0.24^d	14.98 ± 0.18^b
15% LRF	4.50 ± 0.13^b	0.95 ± 0.04^d	4.71 ± 0.15 ^c, d	17.83 ± 0.13 ^c
20% LRF	4.44 ± 0.15^b	0.96 ± 0.04^d	4.66 ± 0.24 ^b	20.45 ± 0.16^e
25% LRF	4.31 ± 0.11^a	1.03 ± 0.06^e	4.17 ± 0.27 ^a	20.61 ± 0.17 ^f

^{a, b, c, d, e f}Mean followed by different letters in the same column differs significantly (P ≤ 0.05). ¹Each value is a mean of three replicates and expressed as mean ± S.D. (n = 3).

*Control represents biscuits without fat replacement.

^{a, b, c, d, e f}Las medias dentro de una columna difieren significativamente (P ≤ 0.05) y se calculan por el método Duncan. Cada valor se expresa como media ± DE (n = 3).

*El control consiste en galletas sin remplazo de grasa.

3.8. Texture and color properties

Fat is an effective lubricant in making soft dough biscuits and, in the presence of fat ingredients, get baked, including gluten and make the texture soft and create appealing mouthfeel. However, in the absence of fat and inclusion of fiber-rich LRF, the texture becomes hard and unacceptable. The hardness of LRF-WF biscuits increased with an increased concentration of LRF is reported in Table 7. Ajila et al. (2008) also reported an increase in breaking strength of biscuits when mango peel powder was incorporated in soft dough biscuits. The addition of 10% LRF and 15% LRF resulted in less hardness as compared to 20% LRF and 25% LRF; this could be attributed to imbalance in hydrophilic and hydrophobic components present in the dough. The higher hydrophilic biopolymers, such as the dietary fibers raise the WAC of LRF-WF blends in case of the higher amount of fat replacement that upon baking makes the texture rigid. Similar results often appear in literature, as reported by numerous researchers showing that hydrophilic components enhanced the WAC of the dough and weakening the complex gluten network that ultimately hardened the texture of the biscuits samples (Ajila et al., 2008). The surface color of the biscuits decreased shown by lightness (L*) and yellowness (b*) as the amount of LRF increased in the biscuits (Figure 2).

Figure 2. Effect of Lotus root flour (LRF) on color profile of biscuits samples. Control represents biscuits without fat replacement.

Figura 2. Efecto de la harina de raíz de loto (LRF) en el perfil de color de las muestras de galletas. El control consiste en galletas sin sustitución de grasa.

In contrast, a* (redness) values were increased with the increased concentration of LRF in the biscuits. Similarly, Jan et al. (2015) observed decreased L* and b* values and increased in a* value in cookies prepared with blends of buckwheat and wheat flours, which may be due to the browning reactions that triggered during baking. Maillard browning and caramelization of sugar are known to produce brown melanoidin pigments during baking, contributing to the color of biscuit (Laguna et al., 2011).

3.9. Nutritional properties

Nutrient composition of LRF of control and fat mimetic biscuits are presented in Table 8. LRF is an excellent source of crude fiber (2.30%), protein (16.31%), and ash content (3.21%). All the fat replaced biscuits showed higher protein, ash, and crude fiber contents than the control. Fat content reduced in biscuits samples with the level of addition of LRF, ranged from 14.01 to 24.01%. As the concentration of LRF increased, the moisture content of biscuit samples slightly reduced. Reduction in moisture content was due to the decrease in the gluten network with the increase in the amount of LRF (Ovando-Martinez et al., 2009). The crude fiber level varied in direct proportion with the amount of LRF. The control sample showed the lowest value of crude fiber (0.21%), while the biscuits containing 25% LRF followed by 20% LRF possessed the highest crude fiber 15.6% and 15%, respectively. The carbohydrate content and energy (kcal) values were highest in control (59.04% and 497 kcal). However, LRF-WF biscuits samples showed less energy values in view of reduced fat content. Similarly, organoleptically superior and nutritionally enhanced biscuits have also been produced earlier by supplementing the pomegranate peel (Ismail et al., 2014).

Table 8. Effect of fat replacement by Louts root flour (LRF) on the nutritional profile of biscuits.

Tabla 8. Efecto del remplazo de grasa por harina de raíz de loto (LRF) en el perfil nutricional de las galletas.

Sample	Moisture content (%)	Ash (%)	Protein (%)	Fat (%)	Crude fiber (%)	Carbohydrate (%)	Kcal/ 100 gm
Control*	5.02 ± 0.12^a	0.53 ± 0.01^a	11.20 ± 0.10^b	24.01 ± 0.20 ^f	0.21 ± 0.26^a	59.04 ± 0.80^e	497
5% LRF	5.01 ± 0.30^b	0.81 ± 0.10^b	10.21 ± 0.50^a	21.33 ± 0.01^a	12.30 ± 0.42^e	41.92 ± 0.30^a	265
10% LRF	5.68 ± 0.14^d	1.73 ± 0.03 ^c	12.70 ± 0.12 ^c	19.21 ± 0.14^e	14.60 ± 0.20^b	45.88 ± 0.42^b	408
15% LRF	5.68 ± 0.10^d	1.77 ± 0.01 ^c	12.90 ± 0.11 ^c, d	18.11 ± 0.10^d	14.80 ± 0.11^b,c	46.94 ± 0.57 ^c	402
20% LRF	5.65 ± 0.11 ^c	2.82 ± 0.02^d	12.60 ± 0.15 ^c	15.32 ± 0.21 ^c	15.00 ± 0.21 ^c	48.61 ± 0.64^d	383
25% LRF	5.64 ± 0.12 ^c	2.86 ± 0.06^d,e	13.40 ± 0.20^e	14.01 ± 0.10^b	15.60 ± 0.13^d	48.79 ± 0.60^d	375

^{a, b, c, d, e, f}Mean in the same column differ significantly (P ≤ 0.05). Each value is expressed as mean ± S.D. (n = 3).

*Control represents biscuits without fat replacement.

^{a, b, c, d, e, f}Las medias dentro de una columna difieren significativamente (P ≤ 0.05) y se calculan por el método Duncan. Cada valor se expresa como media ± DE (n = 3).

*El control consiste en galletas sin sustitución de grasa.

3.10. Sensory analysis

Biscuits with 10% LRF were found to be similar results as the control sample in terms of texture, color, and overall acceptability (Table 9). Fats help in lubricating and softening the dough structure because of restricting interaction of dough components that impart desirable textural properties (Hasmadi et al., 2014). Fat replacement at the level of 15% LRF was not significantly (P ≤ 0.05) different from the control biscuits in terms of appearance, taste, texture, and overall acceptability. However, fat replacement beyond 15% in the biscuits resulted in unpleasant mouthfeel and harder texture, as confirmed from the observations of the texture analyzer (Table 7). In view of the reduced fat content of dough in the dough formulation, the flour protein particles were better hydrated during mixing because of the available excess water for wetting the flour components, consequently higher hydration of gluten and harder dough were obtained that produce harder biscuits on baking (Rodríguez-García et al., 2013). Our observation about the increase in hardness due to fat replacement through LRF was in agreement with similar studies related to the hardness of biscuits increased with the increased level of fat replacement with maltodextrin and polydextrose (Sudha et al., 2007).

Table 9. Effect of lotus root flour (LRF) on sensorial properties of biscuits.

Tabla 9. Efecto de la harina de raíz de loto (LRF) en las propiedades sensoriales de las galletas.

Sample	Color (9)^1	Texture (9)^1	Appearance (9)^1	Taste (9)^1	Overall acceptability (9)^1	Overall score (45)^1
Control^2	8.00 ± 0.55 ^c	8.14 ± 1.41^d	8.00 ± 1.36^e	8.07 ± 1.04^e	8.43 ± 0.85^e	40.64
5% LRF	6.01 ± 1.34^b	6.03 ± 1.10^a	6.71 ± 1.49 ^c	7.12 ± 1.23^d	6.43 ± 0.94^a	32.3
10% LRF	7.57 ± 0.96 ^c	8.17 ± 1.39^d	7.07 ± 1.82^d	7.17 ± 1.26^d	7.36 ± 0.94^d	37.34
15% LRF	8.43 ± 0.92^e	8.16 ± 1.42^d	8.07 ± 1.33^e	7.96 ± 1.35^e	8.39 ± 0.99^e	41.01
20% LRF	7.64 ± 1.01^d	7.29 ± 1.38 ^c	6.29 ± 1.20^b	6.64 ± 1.08^b	7.00 ± 0.88 ^c	34.86
25% LRF	6.00 ± 1.47^a	6.43 ± 1.40^b	5.86 ± 1.51^a	6.36 ± 0.84^a	6.50 ± 0.94^b	31.15

^{a, b, c, d, e}Means within a column differ significantly and calculated by the Duncan method (P ≤ 0.05).¹ 9 Points hedonic scale: 9; like extremely, 8; like very musk, 7; like moderately, 6; like slightly, 5; neither like nor dislike, 4; dislike slightly, 3; dislike moderately, 2; dislike very much, 1; dislike extremely. Each value expressed as mean ± SD. (n; 20 panelists).

²Control represents biscuits without fat replacement.

^{a, b, c, d, e}Las medias dentro de una columna difieren significativamente (P ≤ 0.05) y se calculan por el método Duncan. Cada valor se expresa como media ± DE (n = 3).¹ Escala hedónica de 9 puntos: 9; me gusta mucho, 8; me gusta bastante, 7; me gusta moderadamente, 6; me gusta ligeramente, 5; no me gusta ni me disgusta, 4; me disgusta ligeramente, 3; me disgusta moderadamente, 2; me disgusta bastante, 1; me disgusta mucho. Cada valor se expresa como media ± DE. (n: 20 panelistas).

²El control consiste en galletas sin remplazo de grasa.

4. Conclusion

The worldwide advancement in baking science due to emerging of new technologies and novel concepts in research, the new variety of biscuits are being introduced, such as zero fat, reduced calorie, nutraceutical biscuits, etc. The concept of composite flour using wheat flour blended with the edible waste of fruit, vegetable, cereals, legumes, seeds, etc. to improve the health benefits of different wheat-based food products is now common. This study emphasizes the potential use of LRF, a nutrient-rich underutilized vegetable root flour, as a fat replacer in biscuits preparations. Biscuits samples prepared by incorporating increasing levels of LRF (10 to 25%) resulted in increased TPC, DPPH inhibition, and FRAP as compared to the control. The rheological analysis of the dough revealed that increased concentration of LRF resulted in the increased WA. In view of the sensory acceptability and desired texture comparable to the control, biscuits made from 15% LRF were recommended for home preparation and large scale production. Hence we may conclude that since LRF is a good source of bioactive components such as the dietary fibers and polyphenols with high antioxidant activity, wheat flour replacement with LRF in wheat-based food products will improve the health benefits for the consumers. Furthermore, the present formulation may be considered to enhance the utilization of LRF in the baking industry for cost reduction, nutritional enhancement, and utilization of a food industry waste for commercialization.

Compliance with ethics requirements

This article does not contain any In Vivo studies with human participants (except biscuits sensory test) or animals performed by any of the authors.

Acknowledgments

The help of Ms. Uroosa Ejaz in proof reading of this manuscript is acknowledged. The authors thank Foodpanda for financial support, and also the University of Karachi for partial funding through a Dean Research Grant. The authors are grateful to English Biscuit Manufacturers management, particularly Dr. Zeelaf Munir and Madam Saadia Naveed, for their encouragement and support.

Disclosure statement

There is no conflict of interest.

Additional information

Funding

This article received financial support from University of Karachi and Foodpanda.