Papaya scientifically called Carica papaya L. is an important tropical and subtropical fruit crop native to the central and South American region. Papaya fruit is known for its nutrient content such as vitamin – A, C, and D, minerals viz., magnesium and potassium.  Papaya fruit is consumed as raw fruit and also in value-added product. Papaya fruits are processed into different value-added products such as papaya candy, papaya pickles, Osmo dried papaya sweet, and papaya shake by involving different preservation methods such as drying, preservation, vacuum packing, freezing, pasteurization and canning. The shelf life of papaya fruits is enhanced by value addition technology. Hence an attempt was made to process papaya into papaya malt by incorporating different millets (Mezgebo,  et al.,  (2018), Agrahar et al., (2016), Agrahar et al., (2015), Chagas et al., (2018).  

Materials and Methods

            This present investigation was carried out at Post Harvest Lab, Department of Horticulture, Faculty of Agriculture, Annamalai University, Annamalainagar during 2020-2022. The experiment was carried out in a Completely Randomized Design with four formulations and five replications. Papaya was processed into malt and the effect of processing on the nutritional quality and sensory quality of malt were determined. The sensory evaluation was carried out at monthly intervals for three months during storage. Papaya malt was prepared with four formulations viz., T₁ –Pearl millets, T_2­­ –Ragi, T₃-Varagu, and T₄-Thinai (Fig. 1). Prepared malt was stored up to three months.

            Fully matured papaya fruit was selected and then peeled after washing. Seeds were removed and cut into small pieces then ground into pulp. Millets were Soaked for 8 hours and allowed to germinate at 37°C for 48 hrs and then dried at 180°C for 1 hour. Then millets, cashew, cardamom and country sugar were also ground to powder form. Papaya pulp was transferred to a pan and started cooking. After 10 minutes, according to the formulations, millets powder was added to it then cooking was continued. After 5 minutes, cooked malt was transferred to the vessels. Finally, cashew, cardamom and country sugar were added to it. The cooked malt was kept in a hot air oven till moisture was removed from it and then ground to a fine powder. The prepared malt was sieved (Sieve at 85 mesh) to get uniform size granules and kept in a plastic container. 

The organoleptic quality of papaya processed products was evaluated by the panelists for sensory attributes such as color, taste, flavor, and also overall acceptability. As explained by (Wichchukit and Mahony, 2014) a nine-point hedonic scale was used ranging from like extremely (9) to dislike extremely (1). All samples were presented before the panelists at ambient temperature under normal lighting conditions. Nutritional quality such as pH, TSS (Brix), total sugars (%), protein (%) and moisture (%) were determined. Total sugars (%) and protein (%) were analyzed by the method of AOAC (2004).

Results and Discussion

Among the different formulations of papaya malt, the minimum value for moisture content recorded in T₂ formulated with 40% ragi (10.5%) and the maximum moisture content recorded in T₃ formulated with 40% varagu (12.4%). The moisture content ranged from 10.50% to 12.40%, which is within the optimal range of humidity (6–15%) to ensure good storage (Taruvinga et al., 2014). Lower moisture content might be due to the processing of malt at high temperatures for a long time leading to evaporation of water from malt.   

Reducing sugars and total sugar content in raw papaya fruit are 2.8% and 5.5% (Attri, 2014). Reducing sugar content in prepared papaya malt ranged from 4.41% (T₂) to 3.46% (T₃) (Table 1)among the formulations and the highest value for total sugar content was recorded in treatment T₂ formulated with 40% Ragi (8.45%) and the lowest total sugar content recorded in T₃ formulated with  40% varagu (6.17%).  Papaya contains a high amount of total and reducing sugars (Rai and Chauhan. 2008). Thus, the incorporation of fruits could be the reason for an increase in total and reducing sugars of the malt mixes. The increase in reducing sugar and total sugar might be due to the degradation of starch to sugars by endogenous amylases on malting (Mittal et al., 2004).

Ash content in prepared papaya malt ranged from 3.5% (T₂) to 2.2% (T₃) among the formulations.  Ash content of processed products was lower than the fresh fruit (4%). The lower amount of ash content might be due to the incorporation of mineral elements into cell constituents during the germination process in the malting of millet (Ogbonna et al., 2012).

            The minimum value for protein content recorded in treatment T₃ was formulated with 40% Varagu (7.6%) and the maximum protein content recorded in T₂ was formulated with 40% Ragi (9.3%). An increase in protein content was observed in prepared malt compared with raw fruit (0.6%). A significant increase in the protein content was observed on the malting of millet. The increase in protein content may be due to loss of carbohydrates through oxidation during germination and loss of low molecular weight nitrogen and rinsing of grains Increased protein content might be attributed to the incorporation of millets which contain a good source of protein by 8% and also due to the formation of free amino acids and peptides during malting. This was also reported by Tanya et al. (2013).

The papaya malt produced with ragi (T₂) scored the best in the first month of sensory evaluation among the different formulations (Table 2), with scores of taste (8.1), color (7.9), flavor (8.0), and overall acceptance (7.7). T₁ with pearl millet obtained the second best score in the formulation, followed by T₄ with thinai.

            The lowest score received in the formulation prepared with varagu (T₃) had scores for taste (5.9), color (6.2), flavor (6.1) and overall acceptability (6.5). Sensory evaluation was conducted for another two months, during this time sensory score of all treatment got decreased.

In the third month of evaluation, among the different formulations, the highest score was recorded in T₂ (ragi) with scores for taste (7.4), colour (7.4), flavor (7.5) and overall acceptability (7.2) followed by T₁ and T₄. The lowest scores were recorded in the formulation T₃ (varagu) with a score for taste (5.4), colour (5.6), flavor (5.6) and overall acceptability (6.1).

The presence of bacterial count accounted to 2.3 × 10^-6 cfu and a fungal count of    0.3 × 10^-4 cfu in papaya malt (Table 3). The microbial count was slightly higher in malt. An increase in microbial count might be due to the incorporation of papaya fruit during the production of malt which contains nearly 90 % of moisture as reported by (Badau, 2006).

Conclusion

Finally, it is concluded that among the formulations, T₂ (40% of Ragi) was considered as the best treatment with moisture (10.5%), ash (3.5%), reducing sugar (4.41%), total sugar (8.45%), protein (9.3%). The maximum sensory scores for organoleptic evaluation were obtained by T₂ (40% of ragi) for taste, colour, flavour and overall acceptability followed by T₁ (40% of pearl millet). The cost economics for the production of papaya malt was 1.74. Hence processing of papaya into papaya malt can be commercialized.

Fig. 1 Prepared Papaya Malt

Table 1: Effect of variation in millets on the nutritional quality of papaya malt

Table 2: Mean sensory scoring for Papaya Malt

Table 3: Microbial analysis in papaya malt

REFERENCES

1. A.O.A.C., 2004. Official Methods of Analysis. Association of Official Analytical chemists, Arlington.
2. Attri ,S., A. K. Dhiman, M. Kaushal and R. Sharma. 2014. Development and storage stability of papaya (Carica papaya L.) toffee and leather. Int. J. Farm Sci., 4(3):117-125.
3. Badau, M. 2006. Microorganisms Associated with Pearl Millet Cultivars at Various Malting Stages. Int. J. Food Safety, (8).
4. Mittal, M., S. Srivastava and G. Singh. 2004. Nutritive value of native and malted barnyard millet. Beverage and Food World,32(12): 50-52.
5. Ogbonna, A. C., C. I. Abuajah, E. O. Ide, U. S. Udofia. 2012. Effect of malting conditions on the nutritional and anti-nutritional factors of sorghum grist. The Annals of the University Dunarea de Jos of Galati Fascicle VI – Food Technology, 36(2): 64-72.
6. Rai, S. and A.S. Chauhan. 2008. Quality attributes of drum dried papaya cereal flakes developed from ripe papaya (Carica papaya L.). Elec. J. Env. Agricult. Food Chem., 7(5): 2914-2931.
7. Tanya, L. Swer,  Kamini Devi, T. V. Hymavathi  and J. Dilip Babu. 2013. Development and Evaluation of Fruit Incorporated Pearl Millet, Bajra (Pennisetum glaucum) Malt Drink Mix. Trends in Biosciences, 6 (3): 239-243,
8. Wichchukit, S. and M. Mahony. 2014. The 9-point hedonic scale and hedonic ranking in food science. J. Sci. Food Agric., 95: 2167-2198.
9. Mezgebo, K., Belachew, T., & Satheesh, N. (2018). Optimization of red teff flour, malted soybean flour, and papaya fruit powder blending ratios for better nutritional quality and sensory acceptability of porridge. Food Science & Nutrition, 6(4), 891-903.
10. Agrahar-Murugkar, D., Zaidi, A., & Gupta, C. (2016). Quality evaluation of composite flour laddoo containing sprouted and malted ingredients. Nutrition & Food Science.
11. Agrahar-Murugkar, D., Gulati, P., Kotwaliwale, N., & Gupta, C. (2015). Evaluation of nutritional, textural and particle size characteristics of dough and biscuits made from composite flours containing sprouted and malted ingredients. Journal of Food Science and Technology, 52(8), 5129-5137.
12. Chagas, K., Cipriano, J. L., Lopes, J. C., Schmildt, E. R., Otoni, W. C., & Alexandre, R. S. (2018). The effects of an osmoregulator, carbohydrates and polyol on maturation and germination of ‘Golden THB’papaya somatic embryos. Anais da Academia Brasileira de Ciências, 90, 3433-3447.