Limonia acidissima: Versatile and Nutritional Fruit of India

ABSTRACT

Limonia acidissima (wood apple) fruit is edible and used in very limited food preparations. This fruit as well as different parts of the L. acidissima plant is also used as a folk medicine to treat various ailments and reportedly possesses anti-hyperglycemic and anti-hyperlipidaemic activities. The purpose of the present study was to examine the potential uses and applications of L. acidissima to improve the usage of this unexploited fruit based on its nutritive value. This review summarizes recent pharmacognostical aspects, various applications of this fruit in food and non-food industries, and the experimental research work done on L. acidissima. This review will be helpful to create interest toward the lesser-known facts and less documented work done on L. acidissima. This information may be useful in developing new formulations or enhancing the existing products with more therapeutic or nutritive value.

KEYWORDS:

• Limonia acidissima
• wood apple
• medicinal fruit
• exotic fruit

Introduction

India is blessed by varied agro-climatic conditions which have paved a way to grow variety of fruits in different seasons of the year. The major tropical, subtropical as well as temperate fruit crops are grown simultaneously in different parts of the country. The agro-climatic conditions in some parts of the country are highly suitable for the cultivation of minor fruit crops like jambhul, karonda, phalsa, wood apple, etc.

The Limonia acidissima is the only species of its genus, in the family Rutaceae. Another related species, Feronia limonia popularly known as katbel (elephant apple) is a highly demanding fruit. The L. acidissima is native and common in dry plains of India and Ceylon (Morton, 1987). L. acidissima is a deciduous, slow-growing, erect tree with a few upward-reaching branches bending outwards near the summit where they are subdivided into slender branchlets drooping at the tips. Its fruit is spherical in shape with 5–12.5-cm diameter. The rind is 6-mm thick and grayish-white in color. It has woody and extremely hard outer shell (called as rind) which is very difficult to crack open. Hammer is used to crack the hard rind of L. acidissima fruit. The pulp is brown, mealy, aromatic, resinous, sour, or sweetish with many small white seeds embedded in it. Syrups, drinks, jellies, and jams can be prepared from its sticky pulp (Morton, 1987; Vidhya and Narain, 2011). The fruit may be eaten raw but it has a sour taste and requires sweetening. Realizing the importance of this fruit as a cheap and highly nutritious source, it can be used in a variety of products for human consumption.

Nutritional Composition of Fruits

L. acidissima is a nutrient-rich fruit that contains a surprisingly high amount of protein (10%) and also shows good amount of phenolic content (38.67 mg (GAE)/g DW) and which corresponds to a good source of antioxidants in dried powder (Sonawane and Arya, 2013, 2015). Additionally, the pectin content of the fruit pulp is 3–8%. The fruit contains flavonoids, phytosterols, glycosides saponins tannins, carbohydrates, triterpenoids, vitamins, and amino acids as its chemical constituents (Mahour et al., 2008). There are reports that some coumarins and tyramine derivatives were also isolated from the fruits of Limonia (Ilango and Chitra, 2009).

Chemical Composition of L. acidissima (Pulp) and its Influence on Nutrition

In the present study, potential benefits were shown by nutritional attributes of L. acidissima fruit (Table 1). The moisture content is quite low (6.4%), which may be advantageous in view of increasing the sample’s shelf life. L. acidissima pulp was found to be very rich in carbohydrates (70.14%). There was an appreciable amount of protein (13.8%), making it a good source of protein, while its fiber content is also good. There is an evidence that dietary fiber has a number of beneficial effects related to its indigestibility in the small intestine (Asp, 1996). Pulp has low amount of fat (4.38%) which makes it an ideal diet for overweight people. The energy value of dried pulp is calculated and the value obtained is 375.18 kcal. Pulp was found to contain calcium, magnesium, iron, and zinc in high amounts followed by many other beneficial nutrients (Table 2). L. acidissima seed flours composed of good source of protein and nutrients such as minerals and essential amino acids (Sonawane et al., 2016). A high content of phosphorous can play an important role in bone formation and other essential metabolic activities of the body. Calcium can play a crucial role in providing rigidity to the skeleton besides its involvement in the neuromuscular functions, blood clotting, and many other metabolic processes (Campous et al., 2009). It also contains iron which is used against anemia, tuberculosis, and disorders of growth (Claude and Paule, 1979). Zinc supplementation in diabetes mellitus proved to have antioxidant effect (Roussel et al., 2003). The ascorbic acid content (180 µg/g of dry matter) would fulfill the recommended dietary allowance (RDA) of the National Research Council (1989). It has been reported for its antioxidant and electron donor properties for eight important enzymes in humans (Moncada and Higgs, 1993). Its antihistamine effect can minimize the formation of carcinogenic substances from dietary material and can be used as herbal medicine for the treatment of common cold and other diseases like prostate cancer (Okwu and Emenike, 2006). The presence of vitamin B1 and B2 can help to convert carbohydrates into energy and these are also essential for growth, production of red blood cells, and healthy skin and eyes (Table 2). For such an uncommon vitamin, it is pretty important, especially if you want healthy skin and eyes. The beta-carotene, a precursor of Vitamin A, also helps to build and maintain teeth, bones, and mucous membranes.

Table 1. Nutritional analysis of dried pulp.22

Constituents	Dried pulp (%)
Moisture	6.4
Ash	5.28
Protein	13.8
Fat	4.3
Carbohydrates	70.0
Dietary fiber	1.7

Source: Pandey et al. (2014).

Table 2. Minerals and vitamins content of L. acidissima pulp.22

Analyte	Concentration (µg/g)
Minerals (µg/g)
P	1,137.35
Mg	852.5
Ca	711.8
Fe	23
Zn	23.84
Cu	6.67
Mn	3.64
Sb	0.626
As	ND
Be	ND
Cd	ND
Cr	1.543
Co	ND
Pb	0.163
Li	0.241
Mo	0.263
Ni	0.819
Se	0.768
Sr	ND
Tl	1.930
Ti	0.257
Sn	0.474
Vitamins (µg/g)
Vitamin C	180
Riboflavin (B2)	0.23
Thiamine (B1)	0.31
Beta-carotene	0.04

Source: Pandey et al. (2014).

Medicinal Value of Fruits

L. acidissima has got high medicinal value. Every part of the fruit has got its medicinal property. The fruit is much used in India as a liver and cardiac tonic and when in unripe state, as a means of halting diarrhea and dysentery and for effective treatment for hiccough, sore throat, and disease of the gums (Mondal et al., 2002). Fruit pulp has anti-inflammatory, antipyretic, and analgesic activity (Ahamed et al., 2008). In addition to this, L. acidissima also has hypoglycemic activity, antitumor, larvicidal and antimicrobial activity, and hepato-protective activity (Vidhya and Narain, 2011). Juice of young leaves is given as a remedy for biliousness and intestinal troubles of children. Oil derived from the crushed leaves is applied on itch and the leaf decoction is given to children as an aid to digestion. As little as 50 mg of L. acidissima fruit juice mixed with warm water and sugar is recommended for blood purification and removal of toxins that cause extensive damage to the body (Vasant and Narasimhacharyaa, 2011). These studies suggested the application of the mixture of L. acidissima pulp and repellents on the skin. These studies have suggested that application of the mixture of .L. acidissima pulp and di-methyl benzamide as mosquito repellents which applied on the skin. Studies are underway to ascertain the mechanisms behind the benefits of this mixture on malaria (Lindsay et al., 1998). Findings of a study suggest that treatments with Feronia limonia extract showed significant hypoglycemic activity (Kangralkar et al., 2010).

Antioxidant and Antimicrobial Activity of  L. acidissima

The L. acidissima pulp is found to contain good amount of phenolic content (38.61 mg/g), 3.41 mg/g ascorbic acid, and good in antioxidant activity by ABTS and DPPH assay (Sonawane and Arya, 2013). Sonawane and Arya (2015) performed comparative assessment to understand the influence of storage condition and drying method (tray and infrared drying) on bioactive constituents, in which author suggested that 80ºC is suitable for drying by both the method and maximum retention of bioactive constituent is observed at ambient temperature. The peptides isolated from the L. acidissima seeds possess antioxidant activity (Sonawane and Arya, 2017). The protein hydrolyzate of L. acidissima seeds shows antimicrobial activity at 300 (mg/ml) against Salmonella typhi, Pseudomonas aeruginosa, Escherichia coli,, and Klebsiella pneumoniae (Sonawane et al., 2018).

L. acidissima in Food Industry

The pulp of this fruit is suitable for making food products such as jam, fruit bar, wine, chutney or sherbet, pulp powder, etc. (Poongodi et al., 2013). L. acidissima jams are of two kinds: one is  prepared from a single fruit and the other is prepared from a combination of two or more fruits (Manay and Shadaksharaswamy, 2005).

L. acidissima as Protein Concentrate

A study suggests that L. acidissima seed protein concentrate is rich in protein (77 g/100 g), and possesses essential amino acids. It exhibits considerable protein extractability (95 g/100 g) at alkaline pH 12 and a low solubility (11 g/100 g) at pH 6. Extractable protein (91 g/100 g) can be precipitated at pH 5.5. The WSPC (wood apple seed protein concentrate) had considerable amounts of the essential minerals: calcium, iron, and phosphorous (Narsing Rao et al., 2011).

Dairy-Based Sweets – Burfi

L. acidissima burfi is prepared using cow milk khoa (Sakate et al., 2004). The pulp of L. acidissima was extracted and blended along with seeds in electrical blender to obtain smooth and uniform texture. Three levels of L. acidissima pulp viz. 20%, 30%, and 40% (by weight) and 30%, 35%, 40%, and 45% sugar were investigated. It was observed that 20% L. acidissima pulp with 45% sugar produced a desirable product with desired sensory quality.

L. acidissima squash is prepared by utilizing xanthan gum, sugar, citric acid, and red chili powder (Ghosh et al., 2010). To prepare L. acidissima squash, the fruit pulp along with its seeds and fiber were scooped out and hot-filtered water was added to the pulp (1 L water/kg pulp). Wood apple squash was prepared by using varied levels of pulp (30% and 35%) and xanthan gum (0.25%, 0.30%, 0.35%, and 0.40%), while keeping the citric acid constant at 1%. Sugar syrup, prepared by heating the mixture of sugar, water, and citric acid, was mixed with fruit pulp containing xanthan gum. The mixture was heated at 85°C for 2–3 min. The product could be stored for 150 days in an acceptable condition of 25°C. The L. acidissima squash with 45% TSS 1% acidity in terms of citric acid, 35% pulp, and 0.35% xanthan gum had the best overall acceptability.

RTS Beverage

Ready to serve beverage prepared from L. acidissima pulp using fully ripened fruit (Lande et al., 2010). The pulp was extracted using water for dilution at 0.5, 1, and 2 times using sieves. The pulp was heated to 60°C for 30 min. Acceptable RTS beverage for L. acidissima can be prepared by using pulp 10% TSS 15°Bx and acidity 0.30% (citric acid). The RTS beverage prepared by pasteurization with sodium benzoate added to a (100 ppm) remained in good condition for up to 3 months.

Biscuit

Patel and Pandey (2014) carried out the fortification of bakery products and studied the antioxidant properties of L. acidissima. In this study, an attempt was made to utilize L. acidissimaLinn fruit powder for the fortification of wheat flour, which is used for the development of phenolic-enriched herbal biscuit to supplement scarce phytochemicals having greater antioxidant activity. During this study, it was found that the herbal biscuits developed by the fortification of L. acidissima Linn fruit powder show greater antioxidant activity. The HMF content in biscuit was also found to be significantly arrested by LAFP due to its low sugar and protein content when compared to the wheat flour biscuit. Panelists showed positive responses toward the sensory attributes of developed herbal biscuits. Therefore, nutritional and antioxidant potential of developed herbal biscuits will be beneficial for all age groups of people. The other potential uses of L. acidissima are listed in Table 3.

Table 3. Other potential uses of L. acidissima.

Component	Use	Reference
Seeds	It is good source of protein and protein hydrolyzate is prepared by using BBD design and shows the presence of different bands like amide A, amide I, amide III, and amide VI bands in the protein hydrolyzates.	Sonawane and Arya (2017); Sonawane et al. (2018)
Pectin	The pectin in the wood apple has potential for multiple uses in pectin-short India, but it is reddish and requires purification.	Sivakkolundu and Loganathan (2013)
Rind	The fruit shell is fashioned into snuffboxes and other small containers.	Sivakkolundu and Loganathan (2013)
Gum	The trunk and branches exude a white, transparent gum especially following the rainy season. It is used as a substitute for, or adulterant of, gum Arabic and is also used in making artists’ water-colors, ink, dyes and varnish. It consists of 35.5% arabinose and xylose, 42.7% d-galactose, and traces of rhamnose and glucuronic acid.	Sivakkolundu and Loganathan (2013)
Wood	The wood is yellow-gray or whitish, hard, heavy, durable, and valued for construction, pattern-making, agricultural implements, rollers for mills, carving, rulers, and other products. It also serves as fuel.	Sivakkolundu and Loganathan (2013)
Leaves	The leaves are all used against snakebite and have been studied for antitumor, larvicidal and antimicrobial activity. Oral administration of aqueous extract of leaves produced hepatoprotective activity in albino rats.	Kirtikar and Basu (1995); Manjusha et al. (2004)

L. acidissima as Preservative

The various fruit beverages that are rich in anthocyanin and isolated anthocyanin from fruits found unstable due to chemical parameters like change in pH, bleaching due to preservatives, enzymes, and external processing parameters like temperature, light, etc. (Buchweitz et al., 2013a, 2013b). Sonawane et al. (2020) utilized the various concentrations of protein hydrolyzate, which are extracted from L. acidissima seeds, to delay degradation of isolated anthocyanin from Syzygium cumini (L.). The author suggested that 2% concentration of L. acidissima protein hydrolyzate is effective in delaying the degradation of anthocyanin, which might be due to the presence of various peptides mixture.

Conclusion

There are substantial anecdotal reports indicating that the consumption of L. acidissima could ameliorate a wide range of illnesses. In addition, it can be used as a food ingredient to make processed products like jams, jellies, sweets, and savory chutneys and juice. Rind of L. acidissima can also be used as animal feed as it does not contain any toxic compound. These results also support beneficial health claims. Thus, there is enormous scope for future research and further pharmacological investigation on L. acidissima.