10.5582224473.2017.00148.3 r vegetos- an nternational s ... (potassium meta-bisulphate)...

a SciTechnol journal Research Article Attkan et al., Vegetos 2017, 30:3 10.5958/2229-4473.2017.00148.3 Vegetos- An International Journal of Plant Research E s t d . 1 9 8 8 S o c i e t y F o r P l a n t R e s e a r c h All articles published in Vegetos: International Journal of Plant Research are the property of SciTechnol, and is protected by copyright laws. Copyright © 2017, SciTechnol, All Rights Reserved. International Publisher of Science, Technology and Medicine Process Optimization and Changes in Quality Characteristics of Hot Air Dried Onion Slices ( Allium Cepa L.) Attkan AK 1* , Raleng A 1 and Alam MS 2 Abstract Different experimental combinations for onion dehydration process variables i.e. drying temperature, slice thickness and KMS (potassium meta-bisulphate) concentration were tried using Box- Behnken design of experiments. Response surface methodology (RSM) was utilized to research the impact of hot air drying temperature (50, 60 and 70°C), slice thickness (3, 5 and 7 mm), and pretreatment (0.1, 0.3 and 0.5% K 2 S 2 O 5 ) on the responses viz. drying time, color change, pyruvate content, rehydration ratio of the dried onion slices. The drying process was optimized for maximum rehydration ratio, pyruvate content and minimum color change, drying time within experimental range. The optimum operating conditions using selective quality parameters for KMS concentration, slice thickness and drying temperature was 57.31°C, 3 mm and 0.5%, respectively. An analysis of variance exposed that among the process variables, drying temperature followed by thickness of the slice had the most significant effect on all the product responses. Optimum values of the response parameters, in particular the drying time, color change, pyruvate content and rehydration ratio acquired were 671.6 mins, 3.53, 12.93 μmol/g and 4.98, respectively. Organoleptic evaluation was also carried out and it was found that at drying air temperature of 60°C and 3 mm slice thickness, dried onion slices retain maximum color, flavor, and taste and have maximum overall acceptability. Keywords Onion slices; Drying; Pyruvate content; Rehydration ratio; Response surface methodology; KMS; Organoleptic evaluation *Corresponding author: Attkan AK, Department of Processing and Food Engineering, COAE&T, PAU, Ludhiana 141004, Punjab, India, Tel: +91- 9416713102; E-mail: [email protected] Received: November 24, 2017 Accepted: May 22, 2017 Published: May 25, 2017 Introduction Onion (Allium cepa L.) is one of the most seasoned and most ordinarily utilized vegetable in every part of the world, and finds widespread usage in both fresh as well as in dried forms. It is the most established herb developed and utilized basically in most of the tropical countries. Onion is for the most part known its trademark flavour which adds a delightful taste to almost all the food preparations. Since time immemorial, onion has been for the most part utilized as a part of Indian cooking and culinary properties. Aside from including a heavenly taste and flavour, onion has its own medicinal values. It serves as a decent therapeutic substance for cataract, cardiovascular infection [1], malignancy, tumor [2,3,4,5,6,7], asthma [8], anti-ulcer and anti-gastric cancer agent [9], platelet anti-aggregating agent [10], and anti-hypercholesterolemia [11]. India is the second largest producer of onion with 168.13 lakh tons from an area of 10.51 lakh hectares with the productivity of 16.0 tons/ ha respectively [12]. Onion is well known for its dietary value and for the utility as home grown medicine in India. It contains protein, fat, fibre, iron calcium, phosphorous, potassium, vitamin B and traces of vitamin C. It has both reducing and non-reducing sugar. e most distinctive feature of onion is its pungency, which is due to allyl- propyl disulphide. Onion stalk is palatable and contain great measure of carotene and iron. It is likewise utilized as a part of the treatment of anemia, urinary disorders, bleeding piles and teeth disorders. Processed and value added dried onion has considerable importance in world trade and are made in several forms: flaked, minced, chopped, and powdered. It is also used as a flavour additive in a wide variety of food formulations [13]. It is for the most part exported in the form of dehydrated onion, canned onion and onion pickle. Drying is the only quickest and oldest food preservation method which is a simultaneous heat and mass transfer process in which free water is removed from the fruits and vegetables to reduce deterioration. Onions are generally dried from an initial moisture content of about 86% (wb) to 7% (wb) or less for efficient stockpiling, handling and processing. Dried onions in the form of flakes or powder are in great demand in few sections of the world, for instance UK, Japan, Russia, Germany, Netherlands and Spain [14]. Solar drying is the oldest food preservation method and it is still being widely used in developing countries. In spite of the fact that this technique of drying is modest yet it is connected with the issues like contamination by foreign materials by dirt, dust and insect invasion and in addition uneven drying. erefore, the fundamental challenge has been to preserve the pungency, flavour, and color of onion alongside the desired moisture content as it is responsible for the vast majority of the deteriorative microbial reactions, for safe storage life and rehydration ratio during dehydration process. Onion is a heat- sensitive crop requires suitable dehydration conditions to preserve its organoleptic characteristics. Novel dehydration techniques and pretreatments may be used for onion drying to obtain a product with minimal change in physical, biochemical, nutritional and sensory attributes of high consumer acceptance. Temperature and time of drying are considered to be most effective parameters during dehydration, which unequivocally impact the flavour concentration in onion tissues [15,16]. Researchers have observed that some chemical components of onion is not influenced by drying, viz., ash, fat, protein and fibre, while some others are extensively impacted by drying, viz., sugars, acidity and vitamin C [17]. ere is a need to concentrate the plausibility of drying onion slices with various pretreatment concentrations, slice thickness and drying temperature to get the best quality dried product. Keeping this in view, the present work has been attempted to study the effects of pretreatment, slice thickness and different drying temperature on the quality of dehydrated onion slices. In present study mechanical hot air tray dryer is used due to its many advantages over solar drying. Hot air dryers, for example, the batch cabinet dryer are widely utilized for

10.5582224473.2017.00148.3 r vegetos- an nternational s ... (potassium meta-bisulphate)...

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