Shelf Life Enhancement of Butter, Ice-Cream, and Mayonnaise by Addition of Lycopene

Abstract

Lycopene crystals were incorporated in butter (20 ppm), ice-cream (70 ppm), and mayonnaise (50 ppm) and were analyzed for their sensory characteristics during storage for 4 months. The peroxide value generally increased with the storage time. Higher peroxides and free fatty acids were observed in control samples as compared to that of lycopene-treated products. Lycopene as an antioxidant slowed the development of off-flavor, off-odors, and color changes in lycopene-added butter, ice cream, and mayonnaise during storage as it interrupts the chain of free radicals involved in autoxidation. Results showed that there were insignificant changes in hunter L*, a*, and b* values of butter, ice cream, and mayonnaise during the 4 months of storage. Thus, it could be concluded that lycopene-treated products are in comparison with control market samples. The sensory scores of ice cream, butter, and mayonnaise revealed that the sensory attributes were similar to those of control samples. With increased storage, the sensory scores decreased but a significant decrease was observed in the 4th month of storage for all samples.

Keywords:

• Lycopene crystals
• Butter
• Ice cream
• Mayonnaise
• Storage studies
• Sensory evaluation

INTRODUCTION

Color is one of the most important qualities of foods and food colors constitute a major additive as it enhances the acceptance and appeal of a food item. Natural colors have long faced a set of criticisms: these are more expensive, less stable, and less potent than their synthetic counterparts. Although the use of natural colors in food is an ancient practice, it is gaining increasing importance because of consumer's preference for natural products. The use of natural colors is seen as an ecologically sustainable and non-hazardous process. The joint FAO/WHO Expert Committee on Food Additives recommended that more attention should be paid to methods to reduce the trace element impurities in food colors and so the attention of the food industry has turned to the potential of suitable natural alternatives.[1] Although most natural colors have a higher cost in-use than the corresponding synthetic colors, this has not limited their use as dose levels, which are still relatively low. Natural colors are generally extracted from fruits, vegetables, seeds, roots and microorganisms. They are sometimes called ‘biocolors’ because of their biological origin.[2] Nature produces a variety of brilliant pigments and a number are of commercial value for coloring food, e.g., water-soluble natural colorants, such as anthocyanins and betalains, and oil soluble colorants, such as carotenoids, curcumin, etc. Epidemiological studies strongly suggest that high intakes of vegetables and fruits reduce the risk of some diseases, such as atherosclerosis and cancer.[3–6]

Tomato lycopene has all the advantages to make it an excellent natural food color. It is stable to heat and extreme pH values encountered in food processing, effective in low concentrations, has no off-flavors, and covers the full range of colors from yellow through orange to deep red. Addition of lycopene as a food color depends on the formulation, method of food preparation, and the manufacturing techniques involved. The nutraceutical status of lycopene has accelerated research activities to improve processing factors that lead to maintaining the nutritional as well as sensory quality of tomato product.[7] Lycopene is authorized as a food color in European Commission (EC) and listed as E 160d in Directive 95/45/EC. Council Directive permits the use of the extract as a color in a range of foodstuffs at levels up to 500 mg/kg (expressed as lycopene) but this approval does not extend to the use of lycopene as a food ingredient.[8] Lyc-O-Mato^® application of lycopene has been reported in beverages, powdered beverages, dairy foods, surimi, confectionery, bakery, breakfast cereals, nutritional bars, soups, meal replacement, sauces, salsas, pastas, chips and snacks, and dips and spreads.[9]

The exploitation of by-products of fruits and vegetables processing as a source of functional compounds and their application in food is very much desirable as part of a waste management system. Pomace is a major tomato processing waste that contains good quality of red pigment with aesthetic, as well as health promoting, properties. The lycopene-rich waste can be stabilized and extracted for pigment. Studies could be traced on the utilization of skin, which is an important component of pomace and is rich in lycopene. The research focused on the utilization of tomato waste skin as a source of lycopene pigment and the objective of the present study was to analyze the influence of lycopene as a natural colorant on storage stability of butter, icecream, and mayonnaise.

MATERIALS AND METHODS

Tomato Waste

Tomato pomace was collected from a tomato paste manufacturing unit located in Amritsar, India during the processing season. The tomato skin was separated from the pomace using a flotation-cum-sedimentation system[10] and was used for preparation of lycopene crystals. Standard lycopene and β-carotene were obtained from Sigma Aldrich (St. Louis, MO, USA). Three products selected for studies were butter, ice cream, and mayonnaise due to their high fat content and solubility of lycopene in a non-polar phase. These products were prepared in a laboratory, and lycopene crystals from tomato skin were added for color while market samples were taken for comparison.

Preparation of Lycopene Crystals

Tomato carotenoids were extracted from the tomato processing waste skin.[10] Extracts were combined and then evaporated in a vacuum evaporator (Buchi Labortechnik AG, Flawil, Switzerland). The extracted oleoresin containing lycopene crystals was saponified using alkaline propylene glycol solution (oleoresin:propylene glycol:alkali:water: 5:3:1:1) at 65°C for 2 h. Finally, the water was added to disperse the impurities and filtered through Whatman No. 4 filter paper. The extracted lycopene crystals were dried in a freeze drier (Jouan Nordic A/S, Hovedstaden, Denmark) and kept at -20°C.[11,12]

Microscopy of Lycopene Crystals

Lycopene crystals were mounted on a slide in immersion oil, covered with a cover slip, and observed under a light microscope (Olympus, Tokyo, Japan). The observed images under the light microscope were captured by a digital camera (C-5060, Olympus).

High Performance Liquid Chromatography Analysis

Lycopene extract and crystals from tomato waste skin along with standard lycopene and β-carotene solutions were prepared and filtered through a 0.22-μm filter (Millipore, Billerica, MA, USA). Samples were analyzed on analytical HPLC (Waters, Milford, MA, USA) fitted with an automatic degasser, C-18 column 4.6 × 250 mm, and photo-diode array detector (PDA) (2996, Waters, Milford, MA, USA). A mobile phase of acetonitrile:dichloromethane:methanol (45:10:45 v/v) was degassed by a supersonic bath and filtered through a 0.22-mm filter paper. The detector was set in scan mode, 210–550 nm during the analysis. The column temperature was maintained at 25°C, while flow rate was set at 1 ml/min. A sample volume of 30 μl was injected into the column. The carotenoid content of the extract and crystals obtained from tomato waste skin were measured by comparing peak retention time and area under the chromatographic peak of standard lycopene and β-carotene.[13]

UV Spectrum of Lycopene Crystals

Lycopene crystals extracted from tomato waste skin and the standard lycopene were dissolved in hexane (1 mg/ml) and scanned over the wavelength of 200–800 nm in UV visible spectrophotometer (UV 1700, Shimadzu Co., Ltd., Kyoto, Japan).

Application of Lycopene Crystals from Tomato Waste Skin in Food Products

Butter

Cream was pasteurized at 68.5°C for 30 min and cooled to 13°C in an ice bath. Cream was then churned using electric churns, until butter kernels were formed. The butter milk was separated from the butter kernels by drainage through cheese cloth. The butter was pressed, washed with cold water, and worked with a spatula to remove excess butter milk. Salt (2 g/100 g) and lycopene crystals (20 mg/kg) were added to the butter and again kneaded or mixed for 10 min. The product was packed in plastic jars and kept under refrigerated conditions (4–6°C) along with commercially available butter containing annatto as the coloring agent.

Ice cream

The ingredients used in ice cream formulation were milk fat 10 g/100 g, milk solid not fat 12 g/100 g, sugar 15 g/100 g, stabilizers and emulsifier 0.4 g/100 g, and lycopene crystal 70 mg/kg of ice cream. The ice cream mix was pre heated at 54.4°C, homogenized and pasteurized at 68.3°C for 30 min, and aged (-4°C) for 24 h. Ice cream mixes were frozen in a batch freezer with 75% overrun. Ice cream samples were packaged in 2-liter plastic containers and stored at -25°C for further analysis. A market sample containing synthetic color was also kept for comparative studies.

Mayonnaise

Ingredients used in 1 kg of mayonnaise were rape seed oil, 74 g/100 g; egg yolk, 15 g/100 g; vinegar, 6 g/100 g; sugar, 2 g/100 g; salt, 1.2 g/100 g; mustard flour, 0.5 g/100 g; white pepper, 0.2 g/100 g; potassium sorbate, 0.1 g/100 g; and lycopene crystals, 50 mg/kg of mayonnaise. Mayonnaise was prepared in a polyester beaker of 9.5 cm diameter. The stirrer (Gupta Scientific Works, Ambala, India) used for mixing the ingredients had an impeller of 4.5 cm diameter and 6 blades. The beating of the egg yolk was done in a high speed mixer for 2 min and then all the dry ingredients were added to the beaten yolk and were mixed for another 3 min. Lycopene crystals were dissolved in small amount of oil. One-third of the vinegar was added initially to keep the emulsion free from breaking. Oil containing lycopene crystals was added and mixed properly. A fine stream of oil was added gradually with continuous agitation. The rest of the vinegar was incorporated after all the oil had been added. Mixing of the ingredients was done to the appropriate level until the mayonnaise emulsion had been formed. Mayonnaise was packed in jars and stored at refrigerated temperature (4–6°C). The sample procured from the market also contained lycopene since tomato paste had been used as an ingredient.

Storage Studies

The test and market (control) samples of butter and mayonnaise were stored at refrigerated temperature (4–6°C), whereas those of ice cream were stored at -25°C in a deep freezer. The parameters peroxide value (PV), free fatty acids (FFA), Hunter color values, and sensory properties were studied for 4 months along with control samples.

Ice-cream (20 g) was taken in a separating funnel, 100 ml of hot water was added and shaken vigorously for 10 min to break the emulsion. Ammonium hydroxide (10 ml) was added and heated in a water bath at 60°C for 20 min with occasional shaking. Neutralized ethanol (25 ml) was added and shook well for 10–15 min. Diethyl ether (40 ml) and petroleum ether (60 ml) were added in to the above-prepared sample. A solvent layer was transferred to an already tared flask/dish. The aqueous layer was added back to the separating funnel and extracted with diethyl ether (40 ml) and petroleum ether (60 ml). This extraction was repeated 3 times. The solvent containing fat was evaporated followed by heating at 100°C for 1 h.[14] The butter was kept at 60°C for 2–3 h until water and curd separated completely. The supernatant fat was separated. Mayonnaise (20 g) was taken in an Erlenmeyer flask, and 50 ml of petroleum ether was added. The flask was covered and the mixture was stirred for 20 min. Then 5 g of anhydrous sulphate was added in order to remove water from the mixture. Samples were filtered and ether was evaporated in a vacuum evaporator.

Peroxide Value and Free Fatty Acid

Peroxide value of the fat present in three products was analyzed according to the method described by AOAC.[14] Free fatty acids were determined by dissolving 5 g of fat in 50 ml of neutralized ethanol and titrating with 0.1 N NaOH to obtain a light pink color. Results were expressed in terms of percent FFAs in terms of oleic acid.

Color

Visual color was measured using a Hunter colorimeter (Hunter Associates Laboratory, Reston, VA, USA) in terms of L* (lightness), a* (redness and greenness), and b* (yellowness and blueness). The instrument was calibrated with a standard white tile (L = 90.55, a = -0.71, b = 0.39). A glass petri dish containing the ground pulp was placed above the light source, covered with a white plate and Hunter L*, a*, b* values were measured.

Sensory Evaluation

The samples were evaluated using a 9-point Hedonic scale (1—Extremely dislike; 9—Extremely like) by a semi-trained panel. The panel members were instructed about the product and its characteristics. Panel members were selected based on their performance in initial evaluation trials. Sensory descriptors of the samples were appearance (visual appeal on sight), color (adequacy of hue and uniformity), aroma (olfactory feeling on inhaling the head space volatiles), taste (response of taste bud on masticating), texture (force to chew and consistency on melting), and overall acceptability (likeness as compared to commercial product).[15]

Statistical Analysis

Analysis of variance (ANOVA) and Duncan's multiple range test were done using Statistica 5.0 (StatSoft Inc., Tulsa, OK, USA).

RESULTS AND DISCUSSION

Analysis of Lycopene Crystals

The structures of the lycopene crystals were observed under a light microscope. Microscope images showed a bright red colored needle-like structure. Previous studies have also reported similar structure of the lycopene crystals.[16] The HPLC spectrum of crude lycopene extract, crystals, and standard lycopene and β-carotene are presented in Fig. 1. The results revealed that solvent extract and lycopene crystals of tomato waste skin contained both lycopene and β-carotene. However, the relative concentration of β-carotene was higher in extract in comparison to crystals. It might be due to the loss of β-carotene during the purification process. Further analysis revealed that lycopene crystals prepared from tomato waste skin contained 92.68 g/100 g lycopene and 7.23 g/100 g β-carotene. HPLC chromatogram did not show the presence of other impurities. Previous studies have reported 95% purity for lycopene crystals prepared from tomato paste[17] and 90% purity in the case of crystals from tomato skin.[10] Thus, the present findings were the same as the previous investigations.

Figure 1 HPLC chromatogram of tomato skin extract, lycopene crystals, standard lycopene, and standard β-carotene using a C-18 column eluted with acetonitrile:dichloromethane:methanol (45:10:45) as the mobile phase.

The purity of lycopene was further established by UV spectrum of the lycopene crystals along with a standard one. The spectrums for standard and lycopene crystal over the wavelength of 200–800 nm were similar (Fig. 2). The major three bands of both of the samples coincided at 441.01, 468.5, and 503.5 nm. Prior research also revealed that the major three bands lie in 448–448.2, 471.6–473, and 503.2–504 nm.[18,19] Thus, the present results find support from earlier studies.

Figure 2 The scanning pattern bands of standard lycopene and lycopene crystals.

Peroxide Value

Peroxide value (PV) of butter, ice cream, and mayonnaise is presented in Table 1. The initial PV of the butter sample was 0.35 meq O₂/kg fat that was increased to 1.10 meq O₂/kg fat for the control sample prepared by adding annatto and to 0.53 in the case of the experimental sample prepared by adding extracted lycopene from tomato waste skin. ANOVA showed that there was significant (p < 0.05) change in PV during storage. The PV increased significantly (p < 0.05) in 2, 3, and 4 months of storage in the control butter sample and after 3 and 4 months in the case of the experimental butter containing lycopene. The initial PV of ice cream was 1.58 meq O₂/kg that increased to 3.58 meq O₂/kg fat for the control sample containing permitted artificial color and 2.62 meq O₂/kg fat for the experimental sample containing lycopene. ANOVA showed a significant (p < 0.05)

Table 1 Effect of storage on peroxide value (PV) (meq O₂/kg fat) and free fatty acids (FFA) (oleic acid/100 g fat) of butter, ice cream, and mayonnaise with or without addition of lycopene (n = 3)

	PV						FFA
	Butter		Ice cream		Mayonnaise		Butter		Ice cream		Mayonnaise
Time (months)	(Control)	(Treated ^1 )	(Control)	(Treated ^2 )	(Control)	(Treated ^3 )	(Control)	(Treated^4)	(Control)	(Treated^5)	(Control)	(Treated^6)
0	0.35^a ± 0.042	0.35^a ± 0.042	1.58^a ± 0.057	1.58^a ± 0.041	1.21^a ± 0.124	0.81^a ± 0.078	0.29^a ± 0.035	0.29^a ± 0.028	0.11^a ± 0.014	0.11^a ± 0.014	0.23^a ± 0.057	0.23^a ± 0.049
1	0.39^a ± 0.028	0.35^a ± 0.049	1.84^b ± 0.085	1.60^a ± 0.028	4.64^b ± 0.178	1.64^b ± 0.106	0.29^a ± 0.014	0.29^a ± 0.042	0.11^a ± 0.014	0.11^a ± 0.028	0.23^a ± 0.042	0.24^a ± 0.057
2	0.53^b ± 0.021	0.40^a ± 0.028	2.30^c ± 0.071	1.77^a ± 0.078	6.96^c ± 0.127	2.73^c ± 0.057	0.40^a ± 0.042	0.33^a ± 0.035	0.14^a ± 0.042	0.11^a ± 0.014	0.34^b ± 0.057	0.28^a ± 0.028
3	0.68^c ± 0.057	0.46^b ± 0.049	3.03^d ± 0.120	2.13^b ± 0.064	8.18^d ± 0.141	3.66^d ± 0.085	0.64^b ± 0.057	0.39^b ± 0.049	0.15^a ± 0.049	0.12^a ± 0.016	0.40^b ± 0.049	0.30^a ± 0.042
4	1.10^d ± 0.057	0.53^c ± 0.057	3.58^e ± 0.092	2.62^c ± 0.049	9.49^e ± 0.092	4.74^e ± 0.057	0.88^c ± 0.064	0.45^b ± 0.057	0.19^a ± 0.028	0.12^a ± 0.028	0.52^c ± 0.014	0.36^a ± 0.085
Values with different superscripts in columns are significantly (p < 0.05) different.
Treated^1—20 mg lycopene/kg; Treated^2—70 mg lycopene/kg; Treated^3—50 mg lycopene/kg.

increase in PV with storage; however, least significant difference analysis showed a slow increase in the case of ice cream containing lycopene. In the case of mayonnaise, the initial values of 1.21 and 0.81 meq O₂/kg fat increased to 9.49 and 4.74 meq O₂/kg fat for the control and experimental samples, respectively. ANOVA indicated a significant (p < 0.05) increase in the PV value of mayonnaise with storage while LSD analysis showed significant (p < 0.05) increase in PV after every month of storage in both the cases. However, the increase in PV value was lower in lycopene-containing samples. Previous studies reported that fresh fat should have PV less than 1 meq O₂/kg fat[20] and the product remained accepted up to a PV of 10 meq O₂/kg fat.[21] The effect of four different direct-vat-set commercial starter cultures on the PV of butter was found significant during the 4 months of storage at 4 and 18°C.[22]Gonzalez et al.[23] reported the PV of control ice cream to be 4.12–8.06 meq O₂/kg fat, whereas modified ice cream containing oleic acid gave a PV of 2.91–7.77 meq O₂/kg fat during the 2 months of storage. The PV of mayonnaise containing fish oil, specific structured fish oil, and randomized fish oil was 0.38–14.03, 0.36–5.03, and 0.23–4.77 meq O₂/kg fat during ten weeks of storage.[24] Present results find support from the previous research that there was an increase in PV with storage while the products remained acceptable. Thus, lycopene pigment can be used as a natural color.

Free Fatty Acid

The fat exists in triglyceride form and on hydrolysis produces free fatty acids (FFA) that is considered to be an indicator of quality in fat-rich products. In the present study, butter had a FFA content of 0.29 g oleic acid/100 g fat at the time of preparation, which increased to 0.88 and 0.45 g oleic acid/100 g fat for control and lycopene-containing samples, respectively (Table 1). The ANOVA test revealed a significant (p < 0.05) change in FFA content with storage while LSD analysis indicated a significant change after 3 months of storage in control and test samples of butter.

Ice cream had a FFA content of 0.11 g oleic acid/100 g fat, which marginally increased to 0.12 g oleic acid/100 g for the lycopene-containing sample and to 0.19 g/100 g for the control sample. Mayonnaise had an initial FFA content of 0.23 g oleic acid/100 g fat that increased to 0.52 and 0.36 for control and test samples, respectively. ANOVA showed a significant (p < 0.05) increase in FFA content of mayonnaise during storage for 4 months. LSD analysis indicated a significant increase in FFA content after 2 months of storage. Bakirci et al.[22] showed a significant effect on FFA content in butter containing four different starter cultures. The FFA content of mayonnaise containing tomato seed oil was higher as compared to the mayonnaise containing sunflower oil.[25] The relative lower FFA content in the three products containing lycopene indicated that it acted as an antioxidant and resisted marginally to the hydrolysis of the triglycerides.

Color Analysis

This study aims at utilizing extracted lycopene from tomato waste skin into butter, ice cream, and mayonnaise. This pigment imparts characteristic color to these products, which was measured by Hunter colorimeter in terms of L*, a*, and b* values. The changes in color were observed during the storage studies for 4 months. Butter was prepared by adding two pigments, i.e., annatto and lycopene, for control and test samples, respectively. Annatto gave a light yellow color, whereas lycopene-treated butter was a reddish tone/shade. The initial value of L* for the control butter was 51.62 and that of the lycopene-treated butter was 48.78 (Table 2). Results showed that there were insignificant changes in L* value of both control and lycopene-treated butter during 4 months of storage. The a* value of the control sample reduced from 1.93–1.77 and that of the lycopene-treated sample reduced from 2.36–2.25 during the 4 months of storage. The a* values of experimental butter were higher indicating redness in color. There were insignificant changes in b* values of both control and lycopene-treated butter.

Table 2 Effect of storage on Hunter color values of control and lycopene containing butter (n = 3)

	Hunter color values
	L*		a*		b*
Time (months)	(Control)	(Treated*)	(Control)	(Treated*)	(Control)	(Treated*)
0	51.62 ± 0.15	48.78 ± 0.48	1.93 ± 0.04	2.36 ± 0.25	14.83 ± 0.09	14.17 ± 0.44
1	51.30 ± 0.06	48.56 ± 0.35	1.89 ± 0.03	2.33 ± 0.29	14.50 ± 0.20	14.41 ± 0.37
2	51.13 ± 0.44	49.40 ± 0.22	1.86 ± 0.02	2.32 ± 0.09	14.35 ± 0.11	14.41 ± 0.04
3	50.57 ± 0.22	48.56 ± 0.20	1.80 ± 0.03	2.32 ± 0.27	14.26 ± 0.24	14.38 ± 0.13
4	50.22 ± 0.10	46.37 ± 0.85	1.77 ± 0.05	2.25 ± 0.25	14.13 ± 0.12	14.18 ± 0.09
*20 mg lycopene/kg.

In ice cream, the Hunter L* values of control (73.76–72.60) and lycopene-treated (84.11–83.97) samples varied during the 4 months of storage (Table 3). There were insignificant changes in L* values during the storage studies. In comparison with lycopene-treated ice cream, the hue of the control ice cream was higher, which was due to lemon yellow and raspberry red as a colorant. The Hunter a* value of the control sample reduced from 14.53–13.21, whereas the treated one reduced from 11.56–11.16 during 4 months of storage studies. There were insignificant changes in Hunter a* and b* values of both control and lycopene-treated ice cream.

Table 3 Effect of storage on Hunter color values of control and lycopene containing ice-cream (n = 3)

	Hunter color values
	L*		a*		b*
Time (months)	(Control)	(Treated*)	(Control)	(Treated*)	(Control)	(Treated*)
0	73.76 ± 0.14	84.41 ± 0.31	14.53 ± 0.33	11.56 ± 0.09	28.59 ± 0.17	21.73 ± 0.23
1	73.70 ± 0.16	82.40 ± 0.22	14.43 ± 0.17	11.53 ± 0.21	28.38 ± 0.36	21.71 ± 0.19
2	72.86 ± 0.08	84.40 ± 0.42	14.37 ± 0.53	11.52 ± 0.13	27.90 ± 0.39	21.72 ± 0.14
3	73.01 ± 0.25	84.11 ± 1.01	13.94 ± 0.91	11.36 ± 0.13	27.30 ± 0.36	21.68 ± 0.38
4	72.60 ± 0.20	83.97 ± 0.48	13.21 ± 0.42	11.16 ± 0.73	26.79 ± 0.52	21.29 ± 0.71
*70 mg lycopene/kg.

The Hunter L* value of the control mayonnaise was in the range of 49.52–48.99 and lycopene-treated mayonnaise was in the range of 55.82–53.66 during the 4 months of storage (Table 4). The hue of the control mayonnaise was due to added tomato paste as an ingredient, whereas the hue of experimental mayonnaise was due to the addition of lycopene crystals at 50 mg/kg. During the 4 months of storage studies, there were insignificant changes in Hunter a* and b* values of control and lycopene-treated mayonnaise. The effect of lycopene-rich tomatoes and pepper on the L* and b* values of beef patties packaged in modified atmosphere and stored at 2 ± 1°C showed no trend among the treatments throughout the storage period of 24 days, but CIE a* values showed the significant difference of the antioxidants on the beef patties during the storage period.[^{26 ]}

Table 4 Effect of storage on Hunter color values of control and lycopene containing mayonnaise (n = 3)

	Mayonnaise
	L*		a*		b*
Time (months)	(Control)	(Treated*)	(Control)	(Treated*)	(Control)	(Treated*)
0	49.52 ± 0.31	55.82 ± 0.82	12.60 ± 0.07	10.32 ± 0.16	17.65 ± 0.23	19.95 ± 0.84
1	49.50 ± 0.32	55.76 ± 0.27	12.59 ± 0.36	10.32 ± 1.54	17.65 ± 0.26	19.66 ± 1.30
2	49.52 ± 0.08	55.64 ± 0.87	12.53 ± 0.37	10.31 ± 0.47	17.61 ± 0.34	19.63 ± 0.53
3	49.67 ± 0.40	54.62 ± 0.26	12.33 ± 0.62	10.16 ± 0.88	17.32 ± 0.19	19.51 ± 0.57
4	48.99 ± 0.58	53.66 ± 0.96	12.09 ± 0.73	9.64 ± 1.19	16.90 ± 0.70	19.10 ± 0.97
*50 mg lycopene/kg.

Sensory Characteristics

The sensory attributes in terms of appearance, color, aroma, taste, texture, and overall acceptability for ice cream, butter, and mayonnaise were determined for a period of 4 months. The sensory scores for butter revealed that significant decrease in appearance of control samples occurred during the 3rd month of storage (Table 5). However, lycopene-added butter showed a significant decrease during the 4th month of storage. The sensory scores for color of both butter samples showed a significant decrease during the 3rd month of storage. Scores for aroma did not vary within storage time but the sensory scores for taste, texture, and overall acceptability of control and lycopene-added butter samples varied.

Table 5 Sensory characteristics of butter with or without addition of lycopene (n = 10)

Time (months)	Treatment	Appearance	Color	Aroma	Taste	Texture	Overall acceptability
0	Control	8.58^d ± 0.35	8.68^a ± 0.22	8.59^b ± 0.54	8.73^c ± 0.88	8.32^c ± 1.02	8.58^c ± 0.28
	Treated*	8.47^cd ± 0.47	8.31^bcd ± 0.31	8.47^ab ± 0.81	8.66^c ± 0.51	8.25^c ± 0.57	8.43^bc ± 0.64
1	Control	8.32^bcd ± 0.31	8.51^cd ± 0.36	8.22^ab ± 0.46	8.48^c ± 0.24	8.04^bc ± 0.43	8.31^abc ± 0.87
	Treated*	8.18^bcd ± 0.59	8.17^abcd ± 0.42	8.23^ab ± 0.57	8.31^bc ± 0.65	8.11^bc ± 0.87	8.20^abc ± 0.51
2	Control	7.99^abcd ± 0.21	8.16^abcd ± 0.53	7.96^ab ± 0.95	8.14^abc ± 0.84	7.92^abc ± 0.49	8.03^abc ± 0.52
	Treated*	7.85^abcd ± 0.38	7.94^abc ± 0.24	7.99^ab ± 0.73	8.19^abc ± 0.24	7.89^abc ± 0.26	7.97^abc ± 0.81
3	Control	7.73^abcd ± 0.27	7.82^abc ± 0.29	7.57^ab ± 0.51	7.84^abc ± 0.59	7.61^abc ± 0.54	7.71^abc ± 0.93
	Treated*	7.69^abc ± 0.54	7.58^ab ± 0.34	7.48^ab ± 0.59	7.73^abc ± 0.63	7.48^abc ± 0.87	7.59^abc ± 0.37
4	Control	7.54^ab ± 0.61	7.69^ab ± 0.45	7.33^ab ± 0.82	7.21^ab ± 0.24	6.77^a ± 0.71	7.31^abc ± 0.22
	Treated*	7.31^a ± 0.52	7.45^a ± 0.56	7.24^a ± 0.41	7.09^a ± 0.79	6.89^ab ± 0.45	7.20^a ± 0.48
Values with different superscripts in rows are significantly (p < 0.05) different.
*20 mg lycopene/kg.

The sensory characteristics of control and lycopene-added ice cream revealed non-significant changes in the color score during 4 months of storage (Table 6). Sensory scores for appearance of the control ice cream sample showed significant changes during the 4th month of storage. A similar trend was observed for the sensory scores of aroma, taste, texture, and overall acceptability for control and lycopene-added ice cream.

Table 6 Sensory characteristics of ice cream with or without addition of lycopene (n = 10)

Time (months)	Treatment	Appearance	Color	Aroma	Taste	Texture	Overall acceptability
0	Control	8.83^ab ± 0.58	7.91 ± 1.17	8.39^b ± 1.47	8.07^ab ± 0.78	8.37^b ± 0.84	8.31^b ± 1.00
	Treated*	8.97^b ± 1.02	8.73 ± 0.62	8.50^b ± 1.10	8.48^b ±0.97	8.41^b ± 1.03	8.62^b ± 0.38
1	Control	8.41^ab ± 1.27	7.74 ± 1.14	8.07^ab ± 1.02	7.77^ab ± 0.45	8.05^ab ± 1.07	8.01^ab ± 0.85
	Treated*	8.72^ab ± 1.02	8.67 ± 1.26	8.24^ab ± 1.09	8.21^b ± 0.44	8.08^ab ± 0.74	8.38^b ± 0.37
2	Control	7.54^ab ± 0.43	7.52 ± 0.56	7.64^ab ± 0.51	7.34^ab ± 0.97	7.71^ab ± 0.51	7.55^ab ± 0.42
	Treated*	8.38^ab ± 1.19	8.47 ± 0.89	8.00^ab ± 0.44	7.91^ab ± 0.53	7.79^ab ± 0.79	8.11^ab ± 0.93
3	Control	7.18^ab ± 0.86	7.34 ± 1.08	7.21^ab ± 0.97	6.95^ab ± 1.02	7.19^ab ± 1.04	7.17^ab ± 0.98
	Treated*	8.12^ab ± 0.72	8.34 ± 1.21	7.79^ab ± 1.04	7.68^ab ± 0.85	7.21^ab ± 1.08	7.83^ab ± 1.11
4	Control	6.89^a ± 1.19	7.18 ± 1.01	6.47^a ± 0.84	6.42^a ± 1.12	6.31^a ± 1.16	6.65^a ± 0.51
	Treated*	8.00^ab ± 1.44	8.21 ± 0.41	7.21^ab ± 0.71	7.29^ab ± 1.24	6.74^ab ± 1.23	7.49^ab ± 0.97
Values with different superscripts in rows are significantly (p < 0.05) different.
*70 mg lycopene/kg.

The appearance of control and lycopene-added mayonnaise showed non-significant differences during the first 3 months of storage (Table 7). A significant decrease (p < 0.05) in appearance for both control and lycopene-added mayonnaise occurred during the 4th month of storage. A similar trend for color, aroma, taste, and overall acceptability were observed during the storage of control and lycopene-added mayonnaise. However, the sensory score of both control and lycopene-added mayonnaise decreased significantly (p < 0.05) after 2 months of storage.

Table 7 Sensory characteristics of mayonnaise with or without addition of lycopene (n = 10)

Time (months)	Treatment	Appearance	Color	Aroma	Taste	Texture	Overall acceptability
0	Control	8.65^bc ± 1.17	8.37^c ± 0.41	8.63^c ± 0.49	8.18^c ± 0.36	8.57^de ± 0.87	8.45^c ± 0.34
	Treated*	8.87^c ± 0.84	8.69^c ± 0.36	8.68^c ± 0.59	8.24^c ± 1.01	8.71^e ± 0.49	8.64^c ± 0.37
1	Control	8.23^abc ± 0.46	8.14^bc ± 0.43	8.21^bc ± 0.88	7.81^abc ± 0.87	8.05^bcde ± 0.98	8.09^bc ± 0.87
	Treated*	8.39^abc ± 0.89	8.34^c ± 0.23	8.29^bc ± 0.33	7.89^bc ± 0.57	8.19^cde ± 0.51	8.22^bc ± 1.23
2	Control	7.83^abc ± 1.19	7.84^abc ± 1.04	7.74^abc ± 1.09	7.41^abc ± 0.88	7.52^abcde ± 0.94	7.67^abc ± 0.81
	Treated*	7.94^abc ± 1.07	8.14^bc ± 0.44	7.91^abc ± 1.01	7.35^abc ± 0.27	7.68^abcde ± 0.83	7.80^abc ± 0.54
3	Control	7.45^abc ± 1.54	7.67^abc ± 1.08	7.11^abc ± 0.87	7.09^abc ± 0.84	7.12^abc ± 0.64	7.29^abc ± 0.49
	Treated*	7.68^abc ± 0.89	7.94^abc ± 0.67	7.35^abc ± 1.11	7.17^abc ± 0.57	7.31^abcd ± 0.49	7.49^abc ± 0.77
4	Control	6.64^a ± 0.42	6.83^a ± 1.31	6.47^a ± 1.28	6.28^a ± 1.12	6.47^a ± 0.37	6.54^a ± 0.89
	Treated*	6.89^ab ± 0.24	7.18^ab ± 1.01	6.84^ab ± 1.14	6.41^ab ± 1.01	6.78^ab ± 0.83	6.82^ab ± 0.46
Values with different superscript in rows are significantly (p < 0.05) different.
*50 mg lycopene/kg.

Butter made from a fish oil diet was softer than that of the control diet at 4°C; however, its sensory scores did not vary significantly during the 3 months of storage.[27] Sensory attributes of mayonnaise were significantly affected by the mayonnaise type (standard mayonnaise containing 75% oil and light mayonnaise containing 25% oil), storage temperature, and time. After 2 months of cold and room temperature storage, the most significant differences between two types of mayonnaise were noted (p < 0.05) in color hue, shine, density, and odor characteristic.[28] Sensory parameters indicated that mayonnaise containing tomato seed oil was liked by the panelists as compared to sunflower oil mayonnaise, but the characteristic taste of tomato seed oil was less appreciated over sunflower oil mayonnaise.[25]

CONCLUSION

Results showed that there were insignificant changes in Hunter L*, a*, and b* values of butter, ice cream, and mayonnaise during the 4 months of storage. Storage stability of butter, ice cream, and mayonnaise indicated that the addition of lycopene pigment from tomato waste skin did not have a detrimental effect on their quality during 4 months of storage. Sensory data indicated that products containing lycopene pigment had good consumer acceptability for fresh, as well as stored, products. Thus, it could be concluded that lycopene-treated products are in comparison with control samples. Therefore, lycopene pigment can be added for aesthetic and neutraceutical purposes in these food products.