Nutritional enhancement and sensory quality of fortified papaya-guava fruit bars using defatted soy flour and skimmed milk powder

Introduction

Papaya (Carica papaya L.) and guava (Psidium guajava L.) are important tropical fruits valued for their nutritional quality and economic importance. India is the world's leading producer of papaya, with production exceeding 550 lakh tonnes annually, and the crop ranks fifth after mango, banana, citrus, and guava. Papaya is a rich source of vitamin A and also contains appreciable amounts of B-complex vitamins. Guava, often referred to as the "poor man's apple," is widely cultivated in tropical and subtropical regions. Owing to its hardy nature, high productivity, and excellent nutritive value, it has become an important fruit crop in India, contributing nearly 4% of total fruit production. Guava is especially noted for its high vitamin C and pectin content. Papaya pulp is attractive, mildly flavored, and low in acidity, making it suitable for blending with other fruits. Guava pulp has a characteristic aroma and good gelling properties, which support its use in processed products. Blending these two fruits offers an opportunity to develop nutritious and consumer-acceptable fruit-based products such as fruit bars. Food fortification involves the addition of essential nutrients to improve the nutritional value of foods. Since most fruits are naturally low in protein, fortification with protein-rich ingredients such as defatted soy flour and skimmed milk powder can significantly enhance their nutritional profile. Defatted soy flour is an economical source of high-quality plant protein, while skimmed milk powder provides easily digestible animal protein with very low fat content. Their incorporation in fruit-based products may therefore improve both nutritional value and functional quality. Keeping in this view, experiment nutritional enhancement, quality assessment and sensory evaluation of fortified papaya-guava fruit bars was formulated.

Preparation of Papaya-Guava Pulp

The fruits were washed thoroughly under running tap water, peeled, and cut into small pieces. Pulp was extracted using a mechanical pulp extractor. Seeds were removed from guava pulp using the in-built sieving unit of the extractor.

Development of Fortified Papaya-Guava Fruit Bars

Blended papaya-guava pulp combinations optimized in preliminary trials were fortified with defatted soy flour (4 and 5%) and skimmed milk powder (6 and 8%). The blended pulp was heated with continuous stirring until the total soluble solids (TSS) reached 50 °Brix. The mixture was then cooled slightly and 500 ppm potassium metabisulphite (KMS) was added. The concentrated pulp was spread on aluminium trays coated with a thin layer of ghee to a uniform thickness of 0.5 cm and dried in a cabinet dryer at 60 °C. After five hours of drying, a second layer of equal thickness was applied and drying was continued for a further eight hours. The dried sheets were cooled, cut into rectangular bars (3 × 0.5 cm), wrapped in butter paper, labelled, and stored at ambient temperature (25-35 °C). The experiment comprised ten treatments. Treatment T1 consisted of a blend of 60% papaya pulp and 40% guava pulp of the cultivar Allahabad Safeda, whereas T2 included 50% papaya pulp and 50% guava pulp of the cultivar Lalit. Treatments T3 and T4 were obtained by fortifying the T1 blend with 4% and 5% defatted soy flour (DSF), respectively. Likewise, T5 and T6 were prepared by adding 4% and 5% DSF to the T2 blend. In T7 and T8, the T1 blend was supplemented with 6% and 8% skimmed milk powder (SMP), respectively, while T9 and T10 consisted of the T2 blend fortified with 6% and 8% SMP Allahabad Safeda and Lalit refer to the guava cultivars used in the respective blends, while DSF and SMP denote defatted soy flour and skimmed milk powder. The different treatment combinations in experiment are T1:60% papaya pulp + 40% guava pulp (AS), T2: 50% papaya pulp + 50% guava pulp (L), T3: 60% papaya pulp and 40% guava pulp (AS) + 4% DSF, T4: 60% papaya pulp and 40% guava pulp (AS) + 5% DSF, T5: 50% papaya pulp and 50% guava pulp (L) + 4% DSF, T6: 50% papaya pulp and 50% guava pulp (L) + 5% DSF, T7: 60% papaya pulp and 40% guava pulp (AS) + 6% SMP, T8: 60% papaya pulp and 40% guava pulp (AS) + 8% SMP, T9: 50% papaya pulp and 50% guava pulp (L) + 6% SMP, T10: 50% papaya pulp and 50% guava pulp (L) + 8% SMP Note: AS: Allahabad Safeda, L: Lalit, DSF: Defatted soya flour, SKM: Skimmed milk powder

Physico-Chemical and Sensory Evaluation

Fruit bars were analysed at 0, 30, and 60 days of storage. Two samples per treatment were evaluated for moisture content, TSS, pH, titratable acidity, reducing sugars, total sugars, ascorbic acid, total carotenoids, protein content, microbial load, and sensory quality. Moisture content was determined on a fresh-weight basis. TSS, sugars, acidity, pH and ascorbic acid were estimated following the methods of Ranganna (1986) [3] . Protein content and total carotenoids were determined according to Lowry et al. (1951) [5] and Srivastava & Kumar (2009) [6] , respectively. Microbial count was assessed following Harrigan and McCance (1976) [7] . Sensory evaluation was conducted using a 9-point hedonic scale by a trained panel.

Statistical Analysis

The experiment was laid out in a Completely Randomized Design (CRD). Data were analysed using analysis of variance (ANOVA) following the procedure of Panse and Sukhatme, and treatment means were compared at the 5% level of significance.

The moisture content of the fortified papaya-guava fruit bars did not differ significantly among the treatments during storage at 0, 30, and 60 days. Moisture values ranged from 14.92% in T6 to 15.01% in T1. In T1 (60% papaya pulp + 40% guava pulp, Allahabad Safeda), moisture content declined slightly from 15.01% at 0 days to 14.98% at 60 days, although it remained the highest among all treatments throughout the storage period (Fig 1). The lowest values were recorded in T6 (50% papaya pulp + 50% guava pulp, Lalit + 5% defatted soy flour) with 14.95%, 14.94%, and 14.92% at 0, 30, and 60 days, respectively. The gradual reduction in moisture may be attributed to slow evaporation from the product surface during storage. Comparable results have been reported for sapota-papaya bars and blended fruit leathers. Similar trends in moisture behavior were also documented in sapota-papaya fruit bars by Sreemathi et al. (2008) [10] and in olive-apple blended fruit leather by Khan et al. (2014) [11] .

Total soluble solids (°Brix)

No significant differences in total soluble solids (TSS) were observed among the treatments at 0, 30, and 60 days of storage. The highest TSS values were recorded in treatment T8 (60% papaya pulp + 40% guava pulp, cv. Allahabad Safeda + 8% skimmed milk powder), with readings of 79.24 °Brix at 0 days, 79.79 °Brix at 30 days, and 80.05 °Brix at 60 days of storage (Fig. 1). The lowest TSS value was recorded in treatment T2 (50% papaya pulp + 50% guava pulp, cv. Lalit), which increased to 78.35 °Brix by the end of the 60-day storage period. The gradual increase in TSS during storage may be attributed to the conversion of residual polysaccharides into soluble sugars through acid hydrolysis. These findings are consistent with earlier reports on guava leather (Safdar et al., 2014) [13] and papaya toffee and leather (Attri et al., 2014) [14] .

Significant differences in titratable acidity were observed among the treatments at 0, 30, and 60 days of storage (Fig 2 .) The maximum titratable acidity (0.98%) was recorded in T1 (60% papaya pulp + 40% guava pulp, cv. Allahabad Safeda) and T2 (50% papaya pulp + 50% guava pulp, cv. Lalit) after 60 days of storage. At 0 days, T1 (0.98%) and T2 (0.98%) were statistically at par, followed by T9 (0.91%), which comprised 50% papaya pulp + 50% guava pulp (cv. Lalit) supplemented with 6% skimmed milk powder. The lowest titratable acidity at 0 days (0.83%) was noted in T6 (50% papaya pulp + 50% guava pulp, cv. Lalit + 5% defatted soy flour). A similar trend continued during storage. After 30 days, the highest titratable acidity (0.97%) was again recorded in T1 and T2, followed by T8 (0.89%), while the lowest value (0.82%) was observed in T4 and T6. At 60 days, T1 and T2 continued to show the highest acidity (0.96%), followed by T9 (0.88%), whereas the lowest value (0.80%) was recorded in T6. An increase in the proportion of defatted soy flour in the papaya-guava blend was associated with a reduction in titratable acidity, which may be attributed to dilution of the natural fruit acids by the added flour (Anju et al., 2014) [15] . Overall, titratable acidity declined from 0.98% to 0.80% during the 60-day storage period. This decrease may be due to acid-base reactions and salt formation during storage [16] . Comparable findings have been reported in papaya toffee and leather (Attri et al., 2014) [14] and apricot fruit bars (Sharma et al., 2013) [17] pH Significant differences in pH were observed among the treatments at 0, 30, and 60 days of storage (Fig 2 .) The highest pH values (3.86, 3.86, and 3.87 at 0, 30, and 60 days, respectively) were recorded in T6 (50% papaya pulp + 50% guava pulp, cv. Lalit + 5% defatted soy flour). These values were statistically comparable with T2, T5, T9, and T10, and the same trend persisted throughout the storage period. In contrast, the lowest pH (3.38) at 0 days was recorded in T1 (60% papaya pulp + 40% guava pulp, cv. Allahabad Safeda). The pH of T1 remained unchanged up to 30 days, followed by a marginal increase to 3.39 at 60 days. A slight but consistent increase in pH was observed during storage across all treatments. This gradual rise may be attributed to the formation of free acids and hydrolysis of pectic substances during storage. Similar trends in pH behaviour during storage have been reported in mango pulp (Durrani et al., 2010) [19] and wood apple bars (Vidhya and Narain, 2011) [20] .

The reducing sugar content of fortified papaya-guava fruit bars varied significantly among treatments at 0, 30, and 60 days of storage (Fig. 3). At 0 days, the highest reducing sugar (47.45%) was observed in T8 (60% papaya pulp + 40% guava pulp, cv. Allahabad Safeda + 8% skimmed milk powder), which was statistically comparable with T9 and T10. The lowest reducing sugar content (37.54%) at 0 days was recorded in T4 (60% papaya pulp + 40% guava pulp, cv. Allahabad Safeda + 5% defatted soy flour). During storage, T10 (50% papaya pulp + 50% guava pulp, cv. Lalit + 8% skimmed milk powder) exhibited the highest reducing sugar content, reaching 48.14% at 30 days and 48.94% at 60 days, followed by T8 (48.36%) and T9 (47.34%). The lowest values were consistently observed in T4, with 38.37% at 60 days. Overall, fruit bars fortified with skimmed milk powder maintained higher reducing sugar levels than those supplemented with defatted soy flour. The gradual increase in reducing sugars during storage is likely due to the hydrolysis of polysaccharides into monosaccharides and the conversion of non-reducing sugars into reducing sugars. These results are consistent with previous studies on papaya toffee and leather (Attri et al., 2014) [14] and fortified mango bars (Parekh et al., 2014) [21] .

The total sugar content of fortified papaya-guava fruit bars differed significantly among treatments at 0, 30, and 60 days of storage (Fig. 3.). At 0 days, the highest total sugars (74.45%) were recorded in T8 (60% papaya pulp + 40% guava pulp, cv. Allahabad Safeda + 8% skimmed milk powder), which was statistically comparable to T7 (73.34%). The lowest total sugars (64.32%) were observed in T6 (50% papaya pulp + 50% guava pulp, cv. Lalit + 5% defatted soy flour). During storage, T8 consistently maintained the highest total sugar content, recording 73.32% at 30 days and 72.61% at 60 days, comparable to T7 (71.54% at 60 days). The lowest values were consistently observed in T2 (50% papaya pulp + 50% guava pulp, cv. Lalit), with 63.27% at 30 days and 61.15% at 60 days. The higher sugar content in bars fortified with skimmed milk powder is attributed to its naturally high carbohydrate content. A slight decrease in total sugars during storage may result from acid-catalyzed hydrolysis, converting some sugars into monosaccharides. These findings are consistent with previous reports on papaya toffee and papaya leather (Attri et al., 2014) [14] and wild apricot fruit bars (Sharma et al., 2013) [17] .

Ascorbic Acid (mg/100 g) Significant differences were observed among treatments for ascorbic acid content in fortified papaya-guava fruit bars at 0, 30, and 60 days of storage Fig. 4. At 0 days, the highest ascorbic acid content (133.70 mg/100 g) was recorded in T10 (50% papaya pulp + 50% guava pulp, cv. Lalit + 8% skimmed milk powder), followed by T9 (131.80 mg/100 g), T2 (127.32 mg/100 g), T8 (120.40 mg/100 g), and T7 (118.90 mg/100 g). The lowest content (103.50 mg/100 g) was observed in T4 (60% papaya pulp + 40% guava pulp, cv. Allahabad Safeda + 5% defatted soy flour). After 30 days of storage, T10 retained the highest ascorbic acid (129.50 mg/100 g), followed by T9 (121.10 mg/100 g), while T4 recorded the lowest value (93.60 mg/100 g). At 60 days, T9 exhibited the highest ascorbic acid content (108.40 mg/100 g), followed by T2 (107.32 mg/100 g), whereas the lowest level (81.70 mg/100 g) was observed in T6 (50% papaya pulp + 50% guava pulp, cv. Lalit + 5% defatted soy flour). Fruit bars fortified with skimmed milk powder consistently retained higher ascorbic acid content, likely due to the protective effect of the protein matrix [22] . The gradual decline in ascorbic acid during storage is attributed to its oxidation to dehydroascorbic acid, subsequent conversion to 2,3-diketogluconic acid, and eventual formation of furfural compounds, which contribute to browning. These findings are consistent with previous reports on sapota-papaya bars (Sreemathi et al., 2008) [10] , guava nectar (Karanjalker et al., 2013), and wood apple fruit bars (Vidhya & Narain, 2011) [20] .

Total Carotenoids (µg/100 g) Significant differences were observed among treatments for total carotenoid content in fortified papaya-guava fruit bars at 0, 30, and 60 days of storage Fig. 4. At 0 days, the highest carotenoid content was recorded in T1 (60% papaya pulp + 40% guava pulp, cv. Allahabad Safeda) at 1340 µg/100 g, while T3 (1335 µg/100 g), T4 (1333 µg/100 g), T7 (1334 µg/100 g), and T8 (1332 µg/100 g) were statistically comparable. The lowest carotenoid content at 0 days was observed in T6 (50% papaya pulp + 50% guava pulp, cv. Lalit + 5% defatted soy flour) and T10 (50% papaya pulp + 50% guava pulp, cv. Lalit + 8% skimmed milk powder), both recording 1212 µg/100 g. During storage, T1 maintained the highest carotenoid levels, recording 1195 µg/100 g at 30 days and 1030 µg/100 g at 60 days. The lowest carotenoid content was observed in T2 (50% papaya pulp + 50% guava pulp, cv. Lalit), with 1006 µg/100 g at 30 days and 849 µg/100 g at 60 days. A gradual decline in carotenoid content was evident in all treatments during storage, likely due to the thermolabile and photosensitive nature of carotenoids. These results align with previous findings on papaya toffee and leather (Attri et al., 2014) [14] and sea buckthorn leather (Kaushal et al., 2013) [26] .

Protein (%) Significant differences were observed among treatments for protein content in fortified papaya-guava fruit bars at 0, 30, and 60 days of storage (Fig 5 .) At 0 days, the highest protein content (2.10%) was recorded in T6 (50% papaya pulp + 50% guava pulp, cv. Lalit + 5% defatted soy flour), which was statistically comparable to T3 (2.01%), T4 (2.04%), and T5 (2.08%). The lowest protein content at 0 days (0.96%) was observed in T1 (60% papaya pulp + 40% guava pulp, cv. Allahabad Safeda). During storage, the highest protein content at 30 days was observed in T5 (1.97%), while the lowest was recorded in T2 (0.83%). At 60 days, T4 (60% papaya pulp + 40% guava pulp, cv. Allahabad Safeda + 5% defatted soy flour) maintained the highest protein content (1.82%), comparable to T3, T5, and T6. The lowest protein content at 60 days (0.69%) was recorded in T1. The decline in protein content during storage is likely due to protein degradation and Maillard-type reactions between sugars and amino acids. The incorporation of defatted soy flour effectively enhanced the protein content of the fruit bars, corroborating previous findings on protein-enriched fruit products. The higher protein content observed in T6 (50% papaya pulp + 50% guava pulp, cv. Lalit + 5% defatted soy flour) can be attributed to the incorporation of defatted soy flour, which is naturally rich in protein. The gradual decline in protein content during storage is likely due to its participation in Maillard browning reactions, leading to protein-sugar interactions and reduced measurable protein levels (Anju et al., 2014) [15] . These findings are consistent with previous reports on proteinenriched apricot products (Thakur & Neena, 1997) [27] and sea buckthorn leather (Kaushal et al., 2013) [26] .

Sensory Evaluation of Fortified Papaya-Guava Fruit Bars Colour and Appearance

The evaluation of colour and appearance in fortified papayaguava fruit bars indicated no significant differences among treatments at 0 and 30 days of storage. However, significant differences were observed at 60 days. (Table 1). The highest scores for colour and appearance were recorded in T7 (60% papaya pulp + 40% guava pulp, cv. Allahabad Safeda + 6% skimmed milk powder), with 8.90, 8.85, and 8.75 at 0, 30, and 60 days, respectively, statistically comparable to T2 and T8. The lowest scores were observed in T6 (50% papaya pulp + 50% guava pulp, cv. Lalit + 5% defatted soy flour), with 8.35, 8.15, and 8.00 at the respective intervals. The gradual decline in colour and appearance scores during storage may be attributed to Maillard reactions, enzymatic browning, and polymerization of anthocyanins with other phenolic compounds. These findings align with previous reports on guava leather (Safdar et al., 2014) [13] , wood apple fruit bars (Bhatt & Jha, 2015) [29] , and papaya toffee and leather (Attri et al., 2014) [14] .

Texture

Texture scores varied significantly among treatments, with T7 achieving the highest values (8.85 at 0 days, declining slightly to 8.75 at 60 days), comparable to T1, T2, T8, and T10. The lowest scores were recorded in T5 (50% papaya pulp + 50% guava pulp, cv. Lalit + 4% defatted soy flour) at all storage intervals (Table 1). The improved texture in skimmed milk powder-fortified bars is likely due to its functional properties, whereas defatted soy flour contributed to a firmer and less desirable texture. A gradual decline in texture scores over storage is attributed to moisture absorption and minor structural changes in the fruit matrix. These results are consistent with observations in peach-soy fruit leather (Anju et al., 2014) [15] and papaya toffee and leather (Attri et al., 2014) [14] . Flavour Significant differences were observed among treatments for flavour at 0, 30, and 60 days. At 0 days, T7 exhibited the highest flavour score (8.95), followed by T1 and T9, which were statistically comparable. The lowest score was observed in T6 (8.25) (Table 2). At 30 and 60 days, T7 maintained the highest flavour scores (8.90 and 8.80), comparable to T1, T2, and T9, while T6 recorded the lowest (8.15 and 8.00, respectively). The decline in flavour over storage is likely due to chemical changes and loss of volatile compounds, consistent with previous findings on papaya toffee and leather (Attri et al., 2014) [14] and wood apple bars (Bhatt & Jha, 2015) [29] .

Taste

Taste scores showed significant variation among treatments at all storage intervals. T7 consistently recorded the highest scores (8.85 at 0 days; 8.80 at 30 days; 8.75 at 60 days), comparable to T1, T2, T5, T9, and T10, whereas the lowest scores were observed in T6 (8.21 at 0 days; 8.10 at 30 days; 8.05 at 60 days) (Table 2). The gradual decline in taste during storage may be attributed to fluctuations in acidity, pH, and sugar-acid ratio, corroborating reports on papaya toffee and leather (Attri et al., 2014) [14] and fortified mango bars (Parekh et al., 2014) [21] .

Overall Acceptability

At 0 and 30 days, no significant differences were observed in overall acceptability among treatments; however, significant differences appeared at 60 days. T7 achieved the highest scores (8.88 and 8.83 at 0 and 30 days; 8.76 at 60 days), comparable to T1 and T2, while the lowest scores were recorded in T4 (8.38 and 8.22 at 0 and 30 days) and T5 at 60 days (Fig: 6). The superior acceptability of T7 is attributed to the balanced pulp blend and the incorporation of skimmed milk powder, which enhanced texture, flavour, and colour. The slight decline over storage may be due to compositional changes and loss of colour and flavour. These findings are consistent with previous studies on guava fruit bars (Vijayanand et al., 2000) [30] , aonla dehydrated products (Singh et al., 2006) [31] , and papaya toffee and leather (Attri et al., 2014) [14] .

References

1. NHB. Indian horticulture database 2014-2015. Gurgaon (Haryana): Government of India; 2015.
2. Jain PK, Priyanka J, Nema KP. Effect of fruit processing on quality parameters. Am J Food Technol. 2011;6(6):507-512.
3. Ranganna S. Handbook of analysis and quality control for fruits and vegetable products. New Delhi: Tata McGraw-Hill Publishing Company Limited; 1986. p. 150-280.
4. Saini RSKD, Dhankhar OP, Kaushik RA. Laboratory manual of analytical techniques in horticulture. Jodhpur: Agribios; 2001. p. 10-33.
5. Lowry OH, Rosbrough NJ, Farr AL, Randall RJ. Protein measurement with the Folin phenol reagent. J Biol Chem. 1951;193:265-275.
6. Srivastava RP, Kumar S. Fruit and vegetable preservation. Lucknow: International Book Distributing Company; 2009. p. 35-40.
7. Harrigan WF, McCance ME. Laboratory methods in food and dairy microbiology. London: Academic Press; 1976.
8. Panse VS, Sukhatme PV. Statistical methods for agricultural workers. New Delhi: Indian Council of Agricultural Research; 1985.
9. Ashaye OA, Babalola SO, Babalola AO, Aina JO, Fasoyiro SB. Proximate composition of some tropical fruits. World J Agric Sci. 2005;1(1):50-51.
10. Sreemathi M, Sankaranarayanan R, Balasubramanyan S. Studies on fruit bar preparation. Madras Agric J. 2008;95(1-6):170-173.
11. Khan A, Zeb A, Khan M, Shah W. Nutritional and sensory evaluation of fruit products. Int J Food Sci Nutr Diet. 2014;3(7):134-137.
12. Baramanray A, Gupta OP, Dhawan SS. Fruit preservation studies in Haryana. Haryana J Hortic Sci. 1995;24:102-109.
13. Safdar MN, Mumtaz A, Amjad M, Siddiqui N, Raza S, Saddozai AA. Quality assessment of fruit products. Sarhad J Agric. 2014;30(2):247-256.
14. Attri S, Dhiman AK, Kaushal M, Sharma R. Effect of blending ratios on fruit bar quality. Int J Farm Sci. 2014;4(3):117-125.
15. Anju B, Kumari KR, Anand V, Anjum MA. Studies on papaya-guava bar. SAARC J Agric. 2014;12(1):73-88.
16. Kuchi VS, Gupta R, Tamang S. Evaluation of fruitbased products. J Crop Weed Sci. 2014;10(2):77-81.
17. Sharma SK, Chaudhary SP, Rao VK, Yadav VK, Bisht TS. Nutritional and sensory properties of fruit bars. J Food Sci Technol. 2013;50(4):784-790.
18. Imran R, Khan R, Ayub M. Preservation of fruits. Sarhad J Agric. 2000;16(1):89-93.
19. Durrani Y, Ayub M, Muhammad A, Ali A. Fruit preservation techniques. Int J Food Saf. 2010;12:20-28.
20. Vidhya R, Narain A. Studies on fruit bar development. Am J Food Technol. 2011;6(4):279-288.
21. Parekh HJ, Senapati AK, Lalit BLM, Pandit PS. Evaluation of processed fruit products. J Bioresour Eng Technol. 2014;2(3):34-41.
22. Take MAK, Bhotmange GM, Shastri NP. Effect of on fruit products. J Food Sci. 2012;2(6):5-15.
23. Muralikrishna M, Nanjundaswamy AM, Siddappe GS. Studies on fruit bar processing. J Food Sci Technol. 1969;6:93-98.
24. Aranjalker GR, Singh DB, Rajwade VB. Quality evaluation of fruit products. Int Q J Life Sci. 2013;8(2):631-634.
25. Mir MA, Nath N. Nutritional analysis of fruit bars. J Food Sci Technol. 1993;30(4):279-282.
26. Kaushal M, Sharma PC, Sharma R. Fruit bar development and evaluation. J Food Sci Technol. 2013;50(1):78-85.
27. Thakur N. Development of apricot-soya products and their quality evaluation [MSc thesis]. Nauni (HP): Dr. YS Parmar University of Horticulture and Forestry; 1997.
28. Garcia VC, Zafrilla P, Romero F, Abellan P, Artes F, Barberan FAT. Quality changes in processed fruit products. J Food Sci. 1999;64(2):243-247.
29. Bhatt DA, Jha A. Nutritional evaluation of fruit products. Int J Pharm Sci Res. 2015;6(10):4398-4405.
30. Vijayanand P, Yadav AR, Balasubramanyam N, Narasimham P. Development of fruit-based products. Lebensm Wiss Technol Food Sci Technol. 2000;33(2):132-137.
31. Singh R, Dashora LK, Upadhyay B. Papaya-based confectionery products. Indian Food Packer. 2006;33:914.
32. World Health Organization. Guideline values for food and drinking water. Geneva: World Health Organization; 1994.