PREPARATION OF LACTOSE HYDROLYZED WHEY BEVERAGE
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Date
2004
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Publisher
AAU, Anand
Abstract
The present study was planned and conducted to prepare a lactose hydrolyzed whey beverage. Preliminary trials were conducted to select the rate of addition of lactase enzyme (Maxilact L 2000 from K. mahxanus var. lactis) and suitable conditions for lactose hydrolysis were tried. About 80 % hydrolysis of lactose in whey was achieved when lactase enzyme @ 0.4 ml / lit of whey was added. The pH of the whey was adjusted to 6.6 and hydrolysis was carried out at 37°C / 4 hr. The performance of lactase enzyme was compared in both whey and permeate. The performance of enzyme was superior in permeate compared to whey. In the first phase, effect of different types of whey media, namely whey (W), hydrolyzed whey (HW), permeate (P) and hydrolyzed permeate (HP) with two stabilizers viz. CMC and guar gum @ 0.1 % on body, sedimentation and cloudiness of beverages were studied. From the stabilizers evaluated, guar gum @ 0.1 % was found to improve the sensory quality of beverage significantly and lactose hydrolyzed permeate was preferred as a suitable medium. In the second phase of experiment, two flavours (mango pulp and pineapple juice) were tried in different basic media (W, HW, P and HP) at a level of 15 % for the preparation of beverages. Mango flavour was preferred over pineapple flavour and lactose hydrolyzed permeate (HP) was found the most superior, based on sensory characteristics. In the next phase, two types of flavours (mango and pineapple), two sugar levels (5 % and 7 %), and two levels of stabilizer, guar gum (@ 0.1 and 0.2 %) were explored for the preparation of lactose hydrolyzed permeate beverage. The beverages were subjected to sensory evaluation by trained panel of judges. The richness as well as other sensory characteristics of mango pulp containing beverages were highly accepted with 5 % sugar and 0.1 % level of guar gum. The required tartness in beverage was obtained with the addition of citric acid. The pasteurized (72°C / 15 sec) beverages containing either sorbic acid or sodium benzoate at 0.06 % and 0.03 % (w / v) as a preservatives and control samples were packed in preformed sanitized pouches and stored at refrigerated temperature (7±1°C) to study shelf life of the beverage. During storage, the pH of beverages decreased, acidity increased and SPC and yeast and mould count also increased. These changes were greater in case of control sample compared to beverages containing either sodium benzoate or sorbic acid. It was further found that control sample had a shelf life of 14 days and beverages containing sodium benzoate and sorbic acid had a shelf life of 35 days, however, sodium benzoate was more effective as preservative than sorbic acid. The beverages prepared from the lactose hydrolyzed permeate with mango pulp as flavour, sugar at 5 %, guar gum at 0.1 % and sodium benzoate @ 0.03 % were adjudged as the best. The consumer preferences for the experimental beverage and a market sample revealed that 89 % of consumers extremely liked the beverage as against the market sample, which was liked by only 25 % of the consumers. The estimated cost of production per 200 ml pouch of beverage worked out to be Rs. 2.32 /-.
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Keywords
DAIRY TECHNOLOGY, DAIRYING, A STUDY