Solar Drying: Fundamentals,Applications and Innovations - National ...

More documents

Recommendations

Info

Hii and Ong - Quality Characteristics of Solar Dried Products (Lewicki, 1998; Abbott, 1999; Szczesniak, 2002; Benali, 2004; Perera, 2005; Rahman, 2005). Table 5.1. Selected dried product quality attributes Attribute Physical Chemical Nutritional Biological Sensory Parameters colour, texture, shrinkage, porosity, rehydration, breakage, split flavour, odour, water activity, shelf life calorie, vitamins, minerals, fibres, lipids, proteins, carbohydrates, antioxidants mould, yeast, E. coli, Salmonella, mycotoxins, aflatoxins appearance, odour, flavour, mouthfeel and texture Table 5.2. Critical water activity (a w) to inhibit microorganisms Microorganisms a w Bacteria < 0.85 – 0.86 Yeasts and moulds < 0.62 5.3. QUALITY OF SOLAR DRIED PRODUCTS FROM SELECTED STUDIES The following tables (Table 5.3 – Table 5.7) show the research findings summarized from various solar drying studies for food and non-food type products. The summary covers as much as possible those products that are commonly dried using sun light especially for food products. Further details of the studies can be obtained from the cited papers as indicated in the tables. Table 5.3. Solar dried vegetable products Product type Carrots Type of solar dryer Solar cabinet dryer Major findings - High β-carotene loss was found in solar cabinet dried carrots due to longer drying time and exposure to light leading to oxidation. - Low rehydration ratio was observed due to greater shrinkage in solar dried samples. References Prakash et al. (2004) Sweet potato Green house solar dryer - Solar dried sample showed no significant losses in total carotenoids as compared to sun and hot air dried samples. - Sun drying showed the lowest retention value. Bechoff et al. (2009) Green leaves Indirect so- - Higher losses of β-carotene and ascorbic acid were observed in solar Negi and Roy (2001) 114 Drying of Foods, Vegetables and Fruits
Hii and Ong - Quality Characteristics of Solar Dried Products lar dryer drying as compared to hot air cabinet drying upon storage. - Chlorophyll loss was also higher in solar dried sample. - Retention of the quality parameters of leafy green vegetables was better at faster drying conditions. Spinach, cowpeas, sweet potato and cassava leaves Okra Enclosed solar dryer Solar tent dryer - Maximum retention of ascorbic acid and total carotene was observed in enclosed solar dryer with shade as compared to sun drying. - Sun drying showed minimum retention of these nutrients. - Degradation of vitamin C destruction during solar drying of okra was not influenced significantly by sample thickness. - Vitamin C remained fairly constant after 48 h of drying. - Slice thickness showed no significant effect on the changes in whiteness of the solar dried okra with drying time. Maeda and Salunkhe (1981) Adom et al. (1997) Table 5.4. Solar dried fruit products Product type Lemon slices Type of solar dryer Solar dryer associated with the PV module Major findings - Dried lemon samples with bright colour were observed under complementary solar drying using gradual temperature increment (range 36 – 52°C). - Lesser browning was observed as compared to hot air drying at 60°C. References Chen et al. (2005) Grapes & figs Indirect and direct solar dryers - Vitamin C content of dried fruits was low due oxidation during solar drying especially when the samples were either scalded or sulfurized. - The colour of grapes dried using indirect solar dryer showed high acceptance as compared to the natural dried sample (medium acceptance). - The texture and colour of figs dried using mixed solar dryers showed better acceptance than the natural dried samples. Gallali et al. (2000) Drying of Foods, Vegetables and Fruits 115
Page 1:
Solar Drying:Fundamentals,Applicati
Page 5 and 6:
Solar Drying: Fundamentals, Applica
Page 7:
PREFACE Drying using solar radiatio
Page 11:
Index Chapter No Title / Authors Pa
Page 14 and 15:
Visavale - Principles, Classificati
Page 16 and 17:
Page 18 and 19:
Page 20 and 21:
Page 22 and 23:
Page 24 and 25:
Page 26 and 27:
Page 28 and 29:
Page 30 and 31:
Page 32 and 33:
Page 34 and 35:
Page 36 and 37:
Page 38 and 39:
Page 40 and 41:
Page 42 and 43:
Page 44 and 45:
Page 46 and 47:
Page 48 and 49:
Page 50 and 51:
Table 1.4. Quality and other drying
Page 52 and 53:
It was seen that for all fish, hot
Page 54 and 55:
Page 56 and 57:
Page 58 and 59:
Page 60 and 61:
Page 62 and 63:
Page 64 and 65:
Aware and Thorat - Solar Drying of
Page 66 and 67:
Page 68 and 69:
Page 70 and 71:
Page 72 and 73:
Page 74 and 75:
Page 76 and 77: Aware and Thorat - Solar Drying of
Page 85 and 86: Jangam, Hii, C.L.; S.V. Law, and C.
Page 87 and 88: Hii and Law - Solar Drying of Major
Page 107 and 108: Bala, Jangam, B.K.; S.V. Hossain, a
Page 109 and 110: Bala and Hossain - Solar Drying of
Page 123 and 124: Hii, Jangam, C.L., Ong, S.V. and S.
Page 125: Hii and Ong - Quality Characteristi
Page 129 and 130: Hii and Ong - Quality Characteristi
Page 135: Fadhel, Jangam, M.I., S.V. Recent a
Page 138 and 139: Fadhel - Recent Advancements in Sol
Page 164 and 165: 12. Thangvaravut, H., Chiewchan, N.
Page 166 and 167: 39. Nimmol, C., Devahastin, S. (201
Page 168 and 169: 69. Mujumdar, A. S., & Law, C. L. (
Page 170 and 171: 98. Chung, L. L., Waje, S. S., Thor
Page 172 and 173: 129. Qing-guo, H., Min, Z., Mujumda
Page 176:
Solar Drying: Fundamentals, Applica
show all

Solar Drying: Fundamentals,Applications and Innovations - National ...

Create successful ePaper yourself

Delete template?

Save as template?