Nutritional Quality Characteristics of Different Wild and Underutilized Fruits of Terai Region, Uttarakhand (India)

ABSTRACT

The present study was carried out to analyze the nutritional potential of 25 of the most commonly consumed wild and underutilized fruits in the Terai region of Uttarakhand, India. The result of the different fruits analyzed revealed the richness of different phytochemicals among them. The protein content was found to be higher in Solanum nigrum, Broussonetia papyrifera, and Aegle marmelos, while Terminalia bellerica, Ficus racemosa, and Artocarpus heterophyllus were rich in lipid content. The reducing sugars ranged from 1.1–68.2% and non-reducing sugars varied from 0–6.4%. Vitamin analysis revealed higher ascorbic acid content in Emblica officinalis and Pithecellobium dulce, high riboflavin content in Broussonetia papyrifera and Ficus palmata, and high thiamine content in Artocarpus lakoocha and Solanum nigrum. The phenolic content varied from 32.9–2662.4 mg/100 g, the flavonoids between 1.2–93.8 mg/100 g, and carotenoids ranged between 0–85.7 mg/100 g. These wild fruits proved to be a good source of nutrients. Moreover, these fruit species act as a pool of genetic resources for crop improvement by breeding experiments. It can be suggested to commercialize these fruit species for enhancing the socioeconomic status of weaker section of society.

KEYWORDS:

• Wild fruits
• underutilized fruits
• Uttarakhand
• biochemical analysis

Introduction

Terai is a flat stretch of fine alluvium and clay-rich swamps supporting a patch of wetlands, tall grasslands, and forests. The Terai region in Uttarakhand (TRU) is located to the south of the Himalayan foothills and north of the Indo-Gangetic Plains and is characterized by a high water and humid conditions. The soil contains a large amount of minerals and humus derived from the silt brought down by the rivers from the Himalayas. The climate of the region is humid subtropical. These features of the region make it floristically rich.

The TRU was sparsely populated and inhabited by the local tribals, called Tharus, until the early 1950s (Javed and Rahmani, 1998). With the Indian government’s uninventive land reform policies, large areas of Terai habitats, mainly grasslands and forests, were leased out for human settlements. As a result, extensive patches of TRU were converted into arable croplands and industrial establishments. However, there are certain pockets free from human intervention, which endure to provide a niche for a range of native flora. It is wealth of the local communities as it meets all their fundamental necessities, such as food, fodder, fuel, drugs, timber, gums, and oil, etc. (Ganorkar and Kshirsagar, 2013). An important component of the flora is the diverse variety of wild edible fruits that are used by native communities.

Wild fruits constitute an important component of traditional diets of local communities. Many of these wild fruits are underutilized and seldom eaten. These wild fruits have profitable utility in terms of being a rich source of carbohydrates, proteins, fats, vitamins, minerals, fibers, etc. (Deshmukh and Waghmode, 2011). Moreover, these fruits have a fairly good amount of bioactive compounds, such as flavonoids, antioxidants, phenolics, carotenoids, etc. Thus, these fruits could be better utilized in health promotion crusades.

Moreover, many of these fruits could be processed into value-added products like beverages, juices, pickles, jams, nectars, etc. for special markets where the exotic character of such products as well as the bioactive compounds capable of curing degenerative diseases could be appreciated (Alves et al., 2008). Furthermore, the wild fruit species are a good source of genetic diversity, which could be exploited to raise hybrid varieties of fruits with improved biotic and abiotic stress tolerance.

Environment plays a vital role in the biosynthesis of plant bioactive compounds (Hossain et al., 2008). Therefore, the secondary metabolites in fruits grown in one region may be different from those in the other regions. Regardless of the consumption of these wild fruits in Terai region, no scientific data pertaining to their nutritional value is available to date. Thus, efforts have been made to investigate the various wild fruits and to dive into the nutritional aspects of these wild and underutilized fruits. The study could be useful in exploitation of nutritional aspects of these fruits and conservation of the gene pool of these valuable wild species, which may be useful for further research and crop improvement programs, where the wild relatives of domesticated fruits could be used.

Materials and methods

Collection of material

Various wild fruits (Table 1) were collected from 28.9800° N to 79.4000° E for analyzing their nutritional value by conducting surveys to the villages, forests, and local markets. The collected fruit samples were thoroughly washed to remove attached impurities and blotted dry before biochemical analysis. Subsequently, the samples were oven dried at 60 °C till constant weight and ground separately to a fine powder using a blender, sieved, and stored for nutrient analysis. In a case where fresh samples are required, analysis was done within 2 days of the sample collection.

Table 1. Scientific name of some wild fruits of Terai region, Uttarakhand (India).

	Names
Fruits (scientific name)	English name	Local name
Aegle marmelos (L.) Correa	Stone apple, Indian quince	Bel
Annona squamosa L.	Custard apple	Sharifa, Seetaphal
Artocarpus heterophyllus L.	Jackfruit	Katthal
Artocarpus lakoocha Roxb.	Monkey jack	Badhal, Dheu
Broussonetia papyrifera (L.) Vent.	Paper mulberry	Jangli toot
Coccinia grandis (L.) Voigt	Ivy gourd	Kundru
Cordia dichotoma Forst. F.	Sebestan plum, Clammy cherry	Lasora, Leshwa
Emblica officinalis L.	Indian gooseberry	Amla
Eriobotrya japonica Lindl.	Loquat, Japanese medlar	Lokat
Ficus palmata Forsk.	Punjab fig	Bedu, Phegda
Ficus racemosa L.	Cluster fig, Blue fig	Goolar, Trembal,
Mimusops elengi L.	Spanish cherry, Indian medlar	Maulsari, Bakul
Morus alba L.	White mulberry	Toot, tootri
Morus laevigata Wall.	Himalayan mulberry	Shahtoot
Morus nigra L.	Black mulberry	Shahtoot
Phoenix sylvestris Roxb.	Wild date palm, Silver date	Khajoor
Physalis minima L.	Ground cherry	Rasbhari, Kaali bambol
Pithecellobium dulce (Roxb.) Benth.	Monkey pod, Manila tamarind	Jungle jalebi, Vilaiti imli
Solanum nigrum L.	Black nightshade	Makoy
Syzygium cumini (L.) Skeels	Indian blackberry	Jamun
Terminalia bellerica (Gaertn.) Roxb.	Belleric myrobalan	Bahera
Terminalia chebula Retz.	Chebulic myrobalan	Haradh, Harr
Ziziphus jujube (L.) Karst.	Indian plum	Ber
Ziziphus mauritiana Lamk.	Indian jujube	Ber
Ziziphus nummularia (Burm. f.) Wt. & Arn.	Wild jujube	Jhar beri, Malah

Proximate nutrient analysis

The proximate nutrition analyses were done by various methods, such as Rangana (1979), Allen (1989), and AOAC (2000). Water content was determined by weight difference after oven drying the samples at 60 °C until constant weight, following the official method of AOAC (2000).

Reducing sugar and total sugar content was determined by the anthrone reagent method of Hart and Fisher (1971). Non-reducing sugars were determined by taking a difference of reducing sugars from total sugars. Lipid content was determined by extracting the sample with hexane using a Soxhlet apparatus. The proteins were estimated following Lowry et al. (1951) using Bovin Serum Albumin (BSA) Reagent. Crude fiber was determined by acid and alkaline digestion methods using Fibretec apparatus (Roorkee, Uttarakhand, India).

Total phenolic content was determined by the method of Malik and Singh (1980) with some modifications. Ethanolic extract of 500 mg of the sample was centrifuged at 10000 rpm and treated with five-fold diluted Folin–Ciocalteu reagent followed by the addition of 20% of sodium carbonate. Flavonoid content was assayed by an aluminium chloride colorimetric method (Chang et al., 2002) with quercetin as standard. The carotenoids were determined by the method of Jensen (1978). The methanolic extract was centrifuged at 4000 rpm for 30 min. The supernatant after drying was dissolved in diethyl ether and methanolic potassium hydroxide (KOH) was added to it measuring its absorbance at 450 nm.

The method of Omaye et al. (1979) was followed for estimation of ascorbic acid. Sample was extracted in trichloroacetic acid (TCA), and centrifuged at 3500 rpm for 20 min. After addition of DTC reagent (2, 4-dinitrophenyl hydrazine-thiourea-CuSO₄ reagent), it was incubated at 37 °C for 3 h. It was then allowed to stand for 30 min and the resulting color was read at 520 nm.

For riboflavin content analysis, ethanolic extract of the sample was warmed after addition of potassium permanganate and hydrogen peroxide. Then, after adding sodium sulphate its absorbance was noted at 510 nm. Thiamine content was assayed according to Okwu and Josiah (2006). The wavelength of ethanolic extract of the sample was recorded at 360 nm after addition of potassium chloride solution.

Statistical analysis

The samples were analyzed in triplicate and were presented as means of three determinations ± SD (standard deviation). All of the parameters were statistically analyzed using the Statistical Package for the Social Sciences (SPSS, version 16.0; University of Washington, Seattle, WA, USA) software package and analysis of results was done by using one-way analysis of variance (ANOVA) for mean differences.

Result

In the present article, an attempt has been made to investigate the moisture content, reducing sugars, non-reducing sugars, total lipid contents, protein content, crude fibers, total phenolic content, flavonoids, carotenoids, ascorbic acid, riboflavin, and thiamine content of 25 fruits from TRU. The results are presented in Tables 2 and 3.

Table 2. Nutritional value of some wild fruits of Terai region, Uttarakhand (India).

	Parameters
Fruits	Moisture (% f.w.)	Reducing sugars (% d.w.)	Non-reducing sugars (% d.w.)	Proteins (% f.w.)	Lipids (% d.w.)	Crude fibers (% d.w.)
Aegle marmelos	64.71 ± 1.64^k	6.25 ± 0.05^d	2.07 ± 0.03^de	5.18 ± 0.03^b	0.49 ± 0.40^ef	2.37 ± 0.18^hi
Annona squamosa	67.04 ± 2.42^j	10.19 ± 0.05^c	0.66 ± 0.05^h	2.20 ± 0.28^de	0.28 ± 0.03^h	4.65 ± 0.30^e
Artocarpus heterophyllus	82.06 ± 1.74^ef	2.11 ± 0.03^hi	2.47 ± 0.03^d	4.32 ± 0.55^c	6.22 ± 0.13^b	1.33 ± 0.19^j
Artocarpus lakoocha	88.03 ± 1.70^b	1.11 ± 0.05^j	0.09 ± 0.01^ij	2.57 ± 0.42^d	1.55 ± 0.44^d	2.04 ± 0.09^i
Broussonetia papyrifera	79.88 ± 0.66^fg	3.94 ± 0.02^fg	1.25 ± 0.05^fg	6.95 ± 0.15^a	3.64 ± 0.09^c	2.13 ± 0.17^i
Coccinia grandis	93.32 ± 1.10^a	3.21 ± 0.03^gh	0.94 ± 0.04^g	1.36 ± 0.48^fgh	0.43 ± 0.48^f	1.60 ± 0.26^j
Cordia dichotoma	60.04 ± 0.95^l	5.38 ± 0.02^e	3.16 ± 0.04^bc	1.53 ± 0.31^fg	2.25 ± 0.05^cd	12.12 ± 0.09^a
Emblica officinalis	86.31 ± 1.08b^c	5.16 ± 0.08^ef	0.08 ± 0.06^ij	0.85 ± 0.24^hij	0.24 ± 0.11^hi	3.48 ± 0.36^g
Eriobotrya japonica	87.28 ± 0.92^b	3.78 ± 0.11^g	0.74 ± 0.02^gh	1.33 ± 0.32^fgh	0.50 ± 0.16^e	1.50 ± 0.11^j
Ficus palmata	77.35 ± 0.79^hi	5.75 ± 0.03^de	0.26 ± 0.02^hi	1.50 ± 0.17^fg	0.39 ± 0.23^g	2.53 ± 0.33^h
Ficus racemosa	80.36 ± 0.81^fg	4.84 ± 0.05^f	0.01 ± 0.01^k	1.37 ± 0.32^fgh	7.45 ± 0.13^b	0.58 ± 0.063^k
Mimusops elengi	78.34 ± 0.87^gh	8.90 ± 0.04^bc	6.35 ± 0.05^a	1.42 ± 0.20^fgh	1.26 ± 0.0^6d	1.55 ± 0.42^j
Morus alba	80.61 ± 0.72^f	5.60 ± 0.30^de	1.68 ± 0.03^ef	1.76 ± 0.21^ef	0.44 ± 0.05^f	1.48 ± 0.17^j
Morus laevigata	77.18 ± 0.91^hi	6.67 ± 0.05^cd	1.57 ± 0.02^f	1.51 ± 0.17^fg	0.55 ± 0.08^e	0.73 ± 0.08^k
Morus nigra	82.67 ± 1.51^de	4.96 ± 0.03^f	1.72 ± 0.03^ef	1.07 ± 0.14^ghi	0.50 ± 0.05^e	1.58 ± 0.21^j
Phoenix sylvestris	32.81 ± 1.21^n	68.16 ± 0.07^a	3.05 ± 0.06^c	2.60 ± 0.62^d	0.36 ± 0.04^g	1.37 ± 0.05^j
Physalis minima	76.63 ± 1.38^hi	3.10 ± 0.10^gh	2.85 ± 0.04^cd	1.06 ± 0.73^ghi	0.21 ± 0.05^i	4.50 ± 0.40^e
Pithecellobium dulce	76.14 ± 1.39^i	2.56 ± 0.09^h	0.15 ± 0.04^i	2.53 ± 0.14^d	0.19 ± 0.05^j	5.60 ± 0.26^d
Solanum nigrum	84.52 ± 1.22^cd	1.37 ± 0.04^ij	0.08 ± 0.02^ij	7.05 ± 0.27^a	2.22 ± 0.04^cd	6.43 ± 0.31^c
Syzygium cumini	80.57 ± 0.29^f	12.66 ± 0.14^ab	0.98 ± 0.03^g	0.70 ± 0.09^ij	0.15 ± 0.05^j	0.90 ± 0.07^k
Terminalia bellerica	58.21 ± 0.77^l	1.92 ± 0.06^i	0.17 ± 0.02^i	1.06 ± 0.13^ghi	5.37 ± 0.03^a	7.45 ± 0.05^b
Terminalia chebula	54.29 ± 1.05^m	2.51 ± 0.04^h	0.27 ± 0.05^hi	1.62 ± 0.37^fg	3.95 ± 0.05^c	7.10 ± 0.12^b
Ziziphus jujuba	68.03 ± 0.15^j	6.82 ± 0.09^c	1.84 ± 0.05^e	0.81 ± 0.17^hij	0.20 ± 0.01^i	3.84 ± 0.21^f
Ziziphus mauritiana	87.22 ± 0.80^b	1.41 ± 0.03^ij	3.77 ± 0.07^ab	0.65 ± 0.20^ij	0.59 ± 0.04^e	3.45 ± 0.05^g
Ziziphus nummularia	80.12 ± 0.91^fg	1.44 ± 0.05^ij	3.24 ± 0.04^b	0.45 ± 0.03^j	0.93 ± 0.03^de	3.24 ± 0.04^g
L.S.D. (P ≤ 0.05)	1.93745	0.14725	0.06375	0.0638	0.5244	0.35455
ANOVA (F24,50)	378.772	6.310	4.697	2.136	97.476	470.339

Note. Each value is a mean of three replicates ± SD (standard deviation). Values in the column followed by same letter are not significantly different.

P ≤ 0.05; least significant difference test.

Table 3. Phytochemical analysis of some wild fruits of Terai region, Uttarakhand (India).

	Parameters
Fruits	Ascorbic acid (µg/g d.w.)	Riboflavin (µg/g d.w.)	Thiamine (µg/g d.w.)	Total phenolics (mg/100g d.w)	Flavonoids (mg/100g d.w.)	Carotenoids(mg/100g d.w.)
Aegle marmelos	151.76 ± 1.62^h	0.32 ± 0.02^hij	1.56 ± 0.30^e	146.31 ± 0.61^h	18.96 ± 0.05^hi	0.18 ± 0.01l
Annona squamosa	363.97 ± 1.26^e	1.17 ± 0.04^bcd	1.26 ± 0.20^fg	184.33 ± 0.08^gh	8.45 ± 0.05^l	0.49 ± 0.04^k
Artocarpus heterophyllus	1518.83 ± 1.20^ab	0.55 ± 0.05^fgh	1.03 ± 0.12^g	98.60 ± 0.16^hi	86.93 ± 2.07^b	0.13 ± 0.01^m
Artocarpus lakoocha	963.73 ± 1.56^bc	0.46 ± 0.04^fgh	9.83 ± 0.20^a	325.58 ± 0.91^g	93.83 ± 3.87^a	0.11 ± 0.12^m
Broussonetia papyrifera	1.53 ± 0.75^jk	1.67 ± 0.41^a	3.56 ± 0.40^c	481.94 ± 2.65^fg	36.65 ± 1.22^e	45.31 ± 0.45^b
Coccinia grandis	14.63 ± 0.70^ij	1.10 ± 0.36^cd	0.73 ± 0.04^h	72.56 ± 2.16^i	16.12 ± 2.39^ij	0.43 ± 0.02^k
Cordia dichotoma	0.17 ± 0.05^jk	0.14 ± 0.04^ij	0.40 ± 0.01^ij	80.27 ± 1.10^hi	9.53 ± 0.17^kl	0.092 ± 0.01^n
Emblica officinalis	4450.33 ± 0.75^a	0.54 ± 0.04^fgh	0.33 ± 0.04^ij	2662.35 ± 0.04^a	30.50 ± 0.85^f	0.32 ± 0.01^kl
Eriobotrya japonica	11.13 ± 0.12^j	0.28 ± 0.04^hij	0.23 ± 0.03^j	32.85 ± 0.046^j	22.35 ± 0.05^gh	9.19 ± 0.21^gh
Ficus palmata	171.50 ± 3.90^gh	1.43 ± 0.40^ab	1.23 ± 0.25^fg	986.69 ± 2.43^de	13.94 ± 0.28^j	19.68 ± 2.83^d
Ficus racemosa	54.07 ± 0.17^i	1.20 ± 0.30^bcd	1.43 ± 0.35^ef	1048.22 ± 2.14^d	12.80 ± 0.16^jk	20.56 ± 2.59^d
Mimusops elengi	251.00 ± 0.12^ef	0.31 ± 0.03^hij	3.63 ± 0.25^c	98.32 ± 0.69^hi	55.65 ± 2.42^c	19.53 ± 0.35^d
Morus alba	150.47 ± 0.13^h	0.92 ± 0.04d^e	0.31 ± 0.02^ij	1652.14 ± 0.16^c	13.39 ± 0.11^jk	8.37 ± 0.53^h
Morus laevigata	170.67 ± 0.16^gh	0.76 ± 0.04^ef	0.23 ± 0.02^j	1102.41 ± 0.11^cd	37.88 ± 0.36^e	21.82 ± 0.57^c
Morus nigra	151.67 ± 0.17^h	0.04 ± 0.04^ghij	0.26 ± 0.02^j	878.50 ± 0.06^e	42.07 ± 1.40^d	13.39 ± 0.36^f
Phoenix sylvestris	94.70 ± 0.04^hi	0.71 ± 0.02^efg	0.61 ± 0.01^hi	2547.25 ± 0.05^ab	24.80 ± 1.04^g	3.21 ± 0.25^j
Physalis minima	229.97 ± 0.10^fg	0.36 ± 0.04^hij	1.05 ± 0.04^g	63.21 ± 2.44^i	2.16 ± 0.06^m	3.55 ± 1.42^j
Pithecellobium dulce	1329.30 ± 0.06^b	1.27 ± 0.30^bc	2.60 ± 0.20^d	516.30 ± 0.07^f	85.68 ± 0.04^b	9.75 ± 0.84^g
Solanum nigrum	233.20 ± 0.05^f	0.31 ± 0.03^hij	9.17 ± 0.30^b	73.74 ± 0.06^i	1.15 ± 0.03^m	5.79 ± 0.15^i
Syzygium cumini	193.87 ± 0.34^g	0.13 ± 0.02^j	0.35 ± 0.05^ij	550.89 ± 0.12^ef	95.85 ± 2.44^a	85.69 ± 2.76^a
Terminalia bellerica	452.13 ± 0.03^de	0.40 ± 0.01g^hij	0.50 ± 0.02^hij	85.40 ± 1.94^hi	12.58 ± 2.13^jk	8.97 ± 0.03^gh
Terminalia chebula	467.50 ± 0.04^d	0.40 ± 0.02^ghij	0.61 ± 0.02^hi	84.82 ± 0.41^hi	16.03 ± 1.00^ij	6.72 ± 0.33^i
Ziziphus jujuba	656.80 ± 0.03^c	0.32 ± 0.03^hij	0.27 ± 0.04^j	1305.85 ± 2.31^bc	21.053 ± 1.34^gh	15.88 ± 0.10^e
Ziziphus mauritiana	362.70 ± 0.548^e	0.39 ± 0.01^ghij	0.23 ± 0.03^j	1318.23 ± 0.04^bc	21.98 ± 1.66^gh	16.79 ± 0.07^e
Ziziphus nummularia	650.47 ± 0.05^cd	0.42 ± 0.03^ghij	0.31 ± 0.03^j	1293.73 ± 1.26^c	18.89 ± 0.62^hi	16.69 ± 0.15^e
L.S.D. (P ≤ 0.05)	0.29605	0.02695	0.02825	21.0967	3.8751	1.0651
ANOVA (F24,50)	7.607	20.442	655.304	1.056	446.839	2.437

Note. Each value is a mean of three replicates ± SD (standard deviation). Values in the column followed by same letter are not significantly different.

P ≤ 0.05; least significant difference test.

The moisture content was more than 80% in the fruits of Artocarpus heterophyllus, Artocarpus lakoocha, Emblica officinalis, Solanum nigrum, Morus nigra, Morus alba, Ficus racemosa, Syzygium cumini, Ziziphus mauritiana, and Ziziphus nummularia. Other species contain relatively lower moisture content. The reducing and non-reducing sugar content (% d.w.) in the fruits varied from 1.1–68.2% and 0–6.4%, respectively, as shown in Table 2. The reducing sugar content was found to be highest in the fruits of Phoenix sylvestris, followed by Syzygium cumini, Annona squamosa, and Mimusops elengi. It was low in Artocarpus lakoocha, Terminalia bellerica, Ziziphus mauritiana, and Ziziphus nummularia. Non-reducing sugar content was high in the fruits of Mimusops elengi followed by Ziziphus mauritiana, Ziziphus nummularia, and Phoenix sylvestris and less in Ficus racemosa, Pithecellobium dulce, and Terminalia bellerica. The protein content (% f.w.) was high in the fruits of Solanum nigrum (7.1%), Broussonetia papyrifera (7.0%), and Aegle marmelos (5.2%), and less in Ziziphus nummularia (0.5%) and Z. mauritiana (0.7%) (Table 2). The total lipids (% d.w.) determined for the fruits of various wild edible species varied from 15.4% (Terminalia bellerica) to 0.2% (Syzygium cumini). Crude fiber content (% d.w.) was estimated to be highest in the fruits of Cordia dichotoma (12.12), followed by Terminalia bellerica (7.45), Terminalia chebula (7.10), and Solanum nigrum (6.43).

The ascorbic acid content was high in the fruits of Emblica officinalis (4450 µg/g), Artocarpus heterophyllus (1518 µg/g), and Pithecellobium dulce (1329 µg/g) (Table 3). Broussonetia papyrifera, Ficus palmata, Pithecellobium dulce, and Ficus racemosa recorded 1.67 µg/g, 1.43 µg/g, 1.27 µg/g, and 1.20 µg/g riboflavin, respectively (Table 3). The riboflavin content was much lower in other species. Thiamine content in the fruits ranged between 0.23–9.83 µg/g, the highest being in Artocarpus lakoocha followed by Solanum nigrum and least in Ziziphus nummularia. The total phenolic content of the different fruits are also shown in Table 3. It was highest in Emblica officinalis (2662.35 mg/100 g) followed by Phoenix sylvestris (2547.25 mg/100 g) and lowest in Eriobotrya japonica (32.85 mg/100 g). The flavonoid content of the different fruits ranged from 1.15 to 95.85 mg/100 g of extract (Table 3). The amount was highest in Syzygium cumini followed by Artocarpus lakoocha and A. heterophyllus, whereas it was lowest in Solanum nigrum followed by Physalis minima and Annona squamosa. The carotenoid values varied from 0.092–85.69 mg/100 g. Syzygium cumini (85.69 mg/100 g), Broussonetia papyrifera (45.31 mg/100 g), and Mimusops elengii (19.53 mg/100 g) had the highest carotenoid content while Cordia dichotoma had the lowest carotenoid content among the 25 fruits analyzed.

Discussion

A large section of the tribal communities is practicing agriculture due to an ethnical shift in their culture. However, the wild fruits are still a regular constituent in their diet. The nutritive value of wild fruits from TRU does not seem to differ much more than that of fruits from other regions and the cultivated fruits. Although they are not consumed in large quantities, their role in local communities cannot be ignored.

It has been proved that the regular consumption of fruits provide compounds capable of reducing the risk of various diseases like cancers (Bae et al., 2008; Riboli and Norat, 2003; Wright et al., 2008), cardiovascular diseases (He et al., 2007; Hu, 2003), neurodegenerative diseases, diabetes, osteoporosis (Scalbert et al., 2005), and chronic diseases (Beecher, 1999; Van’t Veer et al., 2000). The chief nutritional elements contributing to these defensive roles are phenolics, flavonoids, vitamins, fibers, etc. (Ruxton et al., 2006; Saura-Calixto and Goñi, 2006). These defensive roles could be due to their reducing, free radical scavenging, metal chelating, and singlet oxygen quenching properties (Ikram et al., 2009).

The results show that the nutrient content of most of the wild fruits studied are much higher as compared to the cultivated fruits, such as apple, banana, mango, guava, sapota, etc. (Nazarudeen, 2010; Sundriyal and Sundriyal, 2001). The protein content in Solanum nigrum (7.05%), Broussonetia papyrifera (6.95%), and Aegle marmelos (5.18%) is much higher than that reported by Sundriyal and Sundriyal (2001) in different cultivated fruits like apple (0.30%), mango (0.60%), and banana (1.30%). In the present investigation, Terminalia bellerica (15.37%), Ficus racemosa (7.45%), and Artocarpus heterophyllus (6.22%) possess much higher lipid content as compared to cultivated fruits like litchi (0.30%), orange (0.30%), guava (0.20%), and apple (0.10%). These findings are in agreement with Jeeva (2009) and Nazarudeen (2010). Crude fiber content of the studied fruits is comparable or higher than other wild and cultivated fruits. Our study results are also in support with the conclusion drawn by Ramullu and Rao (2003) and Nazarudeen (2010). Similarly, sugar content noticed in different wild fruits is also within a comparable range with the cultivated edible fruits as documented by Sundriyal and Sundriyal (2001) and Nazarudeen (2010).

The study also revealed wild edible fruits to be rich in different vitamin types. Vitamin C content of the studied wild fruits ranges between 0.01–445.03 mg/100 g. The findings are in agreement with those of Sundriyal and Sundriyal (2001), Jeeva (2009), Contreras-Calderón et al. (2010), and Nazarudeen (2010). The riboflavin content was found to be lesser whereas total thiamine content was higher than different edible fruits as reported by Mitra et al. (2008). Total phenolic content of the fruits studied varied from 63.21–2662.35 mg/100 g. Similarly, Hossain et al. (2008), Ikram et al. (2009), and Contreras-Calderón (2011) also reported higher phenolic content in various edible fruits of Bangladesh, Malaysia, and Colombia, respectively. Flavonoids and carotenoids are also within a range as reported by Loganayaki and Manian (2010) and Murillo et al. (2012).

These species have also been identified as critical resources for long-term ecological security as they are resistant to biotic and abiotic stresses growing in diverse habitats and climatic conditions. Such species may be encouraged for commercial production, which may enhance socioeconomic status of the tribal population. It will also help in the germplasm conservation of these resources. Furthermore, it is required to initiate research focusing the genetic improvement and manipulation through tissue culture, genetic engineering, and plant breeding on various wild edible species. Keeping in view the amount of genetic diversity of wild and minor fruits present in the TRU and its value and potential uses, there is no doubt that this precious wealth can be turned into gold mines to the overall economically weak section of the region.

Funding

We are grateful to Kurukshetra University, Kurukshetra, for providing laboratory facilities and financial assistance to carry out the research work.

Additional information

Funding

We are grateful to Kurukshetra University, Kurukshetra, for providing laboratory facilities and financial assistance to carry out the research work.