INFLUENCE OF WATER ACTIVITY, pH, HEAT TREATMENT AND PRESERVATIVE ON CHEMICAL CHANGES IN CANNED INDIAN COTTAGE CHEESE (PANEER) DURING STORAGE

Abstract

ABSTRACT Influence of water activity (Aw), pH and heat treatment on the chemical changes such as Maillard browning, oxidation and lipolysis in canned paneer has been studied by response surface methodology. Browning in canned paneer in terms of hydroxymethylfurfural content increased during storage; however, it was pH dependent. At pH above 5.0, the rate of browning decreased as Aw increased from 0.90 to 0.98. At pH below 5.0, the rate increased with increased Aw from 0.90 to 0.98. Maximum browning rates were observed at pH 5.2–5.6, low Aw values (0.90–0.92) and high heat treatment levels (up to F value 0.8). At all pH levels, increased Aw increased the oxidation rate, more so at low pH levels. Up to an F value of 0.3, heat treatment seemed to have aided the oxidation rate, but higher F values retarded the oxidation rate, more so at low Aw. Lipolysis occurred during storage, but pH had little effect on the rate of lipolysis. High Aw supported high lipolysis rates.PRACTICAL APPLICATIONSRaw paneer (Indian cottage cheese), popular with people in Indian subcontinent and with Indian diasporas scattered in several countries, has a shelf life of less than a day at ambient temperatures. Several attempts are being made by workers to improve the shelf life of paneer by canning process so that its market within the country and abroad improves. However, canning at usual canning time–temperatures is leading to intense chemical changes in paneer, which is not being accepted by consumers. Authors have tried to obviate such unacceptable chemical changes by reducing the intensity of canning process by adjusting so called “hurdles” of the product by hurdle technology. The present paper is a part of that attempt describing the chemical changes in paneer subjected to low heat intensity canning process with altered “hurdles.” Because the chemical changes occurring in a food product are a function of various parameters called “hurdles” like pH, water activity, heat treatment, etc., the present work attempted to identify the combination of the “hurdles” at which chemical changes are the slowest, which may find better acceptance with consumers.