Effect of Various Pretreatments on Dehydration of Onion and Garlic
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Date
2019
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MPUT, UDAIPUR
Abstract
Onion (Allium cepa L.) and garlic (Allium sativum L.) have been cultivated since antiquity as vegetable and flavouring agents due to their characteristic pungent flavour. Dehydration widely accepting carried way of preservation of products. Dehydrated onion and garlic can be used in several processed or ready-to-eat foods instead of raw. Pretreatment is widely used before drying for agro-products to inactivate enzymes, enhance drying process and improve quality of products. Therefore, the present work has been undertaken to study the effects of various pretreatments on dehydration of onion and garlic.
Fresh onion and garlic procured local market were sliced and pretreated with chemicals before drying. Onion was pretreated with CA, KMS and NaCl while garlic was pretreated with CA, KMS and EDTA for different pretreatment levels and dried in mechanical tray dryer at 50 oC. The quality of dried onion and garlic was determined and the process variables were optimized by I- optimal techniques of multiple regression used.
The rehydration ratio of CA, KMS and NaCl pretreated onion was in the range from 3.76 to 4.06, 4.53 to 4.83 and 2.87 to 3.73 respectively. Pretreated onion with 0.75 per cent KMS had lighter colour (L = 85.9) than with other pretreatments while onion with 12.5 per cent NaCl showed was dark colour (L = 75.28). Similarly, yellowness was maximum (b = 28.32) for 5 per cent NaCl pretreatment. The pyruvate content ranged from 10.2 to 10.9, 11.9 to 12.8 and 9.8 to 8.6 μmol/g for CA, KMS and NaCl pretreated onions respectively.
The rehydration ratio of pretreated garlic ranged from 2.24 to 2.59, 2.49 to 2.98 and 2.24 to 2.59 for CA, KMS and EDTA pretreated garlic respectively. Garlic pretreated with 1.0 per cent KMS was brighter (L = 85.95) than other samples and 0.5 per cent EDTA pretreated sample yellower (b = 17.57) than other samples. The allicin content ranged from 20.6 to 22.4, 20.4 to 24.6 and 19.6 to 24.1 μg/ml for CA, KMS and EDTA pretreated garlic respectively.
Description
Effect of Various Pretreatments on Dehydration of Onion and Garlic
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Nagar C.K.