Khoa and khoa based traditional dairy products: preparation, spoilage and shelf life extension.

Khoa and khoa based products (burfi, peda, kalakand, milk cake, etc.) are a category of traditional dairy products of Indian subcontinent. They are prepared by open pan desiccation along with stirring and scraping of milk to the desired consistency, followed by addition of sugar and / or colour and flavoring ingredients. The peculiar sensory attributes developed during their course of preparation makes them unique, but their short shelf-life is a major challenge faced by the dairy industries. They are spoiled mainly because of yeast and mold growth along with detrimental changes in the sensory attributes. This review describes various preservation techniques explored in the last two decades such as packaging interventions, modified atmospheric and active packaging, chemical preservation, water activity modification, natural preservation, thermal treatments, bio-preservation, etc. which can be used either singly or in combination (hurdle technology), to enhance the shelf life of these milk products.

Modelling and optimization of process parameters for production of desiccated Chhana-murki (Indian cottage cheese-based dessert).

In the present study, process parameters were optimized for the production of desiccated chhana-murki (Indian cottage cheese-based dessert). Response Surface Methodology (RSM) was employed to explore the mutual effects of coagulation temperature (CT) of milk (70-90 °C), % fat level in milk (3.5%-5.5%), and sugar-to-paneer cube (SP) ratio (0.6-0.9) on instrumental hardness (N), water activity (aw), yield (%), sensory sweetness and overall acceptability (on 100-point intensity scale) of chhana-murki. The resulted responses were evaluated by analysis of variance (ANOVA), and the second-order polynomial response surface equations were fitted using multiple regression analysis. Determination coefficients (R 2) were equal to 80% or higher for individual responses stated that the developed models were well fitted to the experimental results. The optimized product was prepared using CT 79.22 °C, milk fat 4.8%, and SP ratio 0.7. Confirmatory experiment values for instrument hardness, water activity (aw), yield (%), sensory sweetness and overall acceptability were 105.05 N, 0.85, 115.2%, 61.2 and 78.8, respectively.

Stability and quality of herb (Pueraria Tuberosa)-milk model system.

The medicinal benefits of herbs could be conveyed via certain foods as carriers. Milk is one of the important carrier which has been effectively used to deliver phytochemicals presents in herbs (mainly polyphenols) for targeted health benefits in the traditional Indian system of medical science. The present study was conducted to evaluate the effect of herb components (Pueraria tuberosa) on properties of Pueraria tuberosa-milk model system. The herb was added into cow milk on the basis of sensory evaluation (0.4 %) by using 9-point hedonic scale. The physical and chemical changes were evaluated after various processing treatments viz. pasteurization (72 °C, 15 s), sterilization (121 °C, 15 min), separation etc. These changes were determined using viscosity, hydroxy methyl furfural (HMF) value, ethanol stability, colour characteristics and trolox equivalent antioxidant capacity (TEAC). It was observed that addition of Pueraria tuberosa to milk resulted in decreased HMF content, ethanol stability and lightness whereas antioxidant activity, redness and yellowness increased as compared to control. It can be concluded that addition of Pueraria tuberosa to milk at 0.4 % concentration altered the functional properties of milk and Pueraira tuberosa could be suitable for preparation of low heat treated functional dairy food products.

Effect of Asparagus racemosus (shatavari) extract on physicochemical and functional properties of milk and its interaction with milk proteins.

The effects of interaction of Asparagus racemosus (shatavari) with milk constituents and physico-chemical and functional characteristics of milk was studied. Addition of freeze dried aqueous shatavari extract at a concentration of 1 g /100 ml of milk showed a decrease in pH, rennet coagulation time and an increase in acidity, viscosity and heat stability at maximum. The extract also imparted brown colour to milk and showed an increase in a* (redness) and b* (yellowness) values but a decrease in L* (lightness) value. Proteins in milk were modified by reaction with shatavari extract. The derivatives formed were characterized in terms of SDS-PAGE. Electrophoretic pattern of sodium caseinate and whey containing 1% shatavari herb extract did not show any difference in band pattern i.e. there was no difference in mobility based on size of the proteins, but the intensity (width) of bands differed.

Potential herbs and herbal nutraceuticals: food applications and their interactions with food components.

Since ancient times, herbs have been used as natural remedies for curing many physiological disorders. Traditional medicinal literature appreciated their value as nature's gift to mankind for the healing of illnesses. Some of the herbs have also been used for culinary purposes, and few of them have been used in cheese manufacture both as coagulating agents and flavor ingredients. Scientific investigations regarding biological activity and toxicity of chemical moieties present in many herbs have been carried out over a period of time. Consequently, literature related to the use of herbs or their functional ingredients in foods and their interaction with food constituents has been appearing in recent times. This article presents the information regarding some biologically active constituents occurring in commonly used herbs, viz., alkaloids, anthraquinones, bitters, flavonoids, saponins, tannins, and essential oils, their physiological functionalities, and also the description of few herbs of importance, viz., Asparagus racemosus, Withania somnifera, Bacopa monniera, Pueraria tuberose, Emblica officinalis, Terminalia chebula, Terminalia belerica, Terminalia arjuna, and Aloe vera, in terms of their chemical composition, biological functionality, and toxicity. This article also reviews the use of herbs and their active ingredients in foods and their interactions with different food constituents.

Effect of added herb extracts on oxidative stability of ghee (butter oil) during accelerated oxidation condition.

The antioxidant activities of vidarikand (Pueraria tuberosa), shatavari (Asparagus racemosus) and ashwagandha (Withania somnifera) extracts (aqueous and ethanolic) were evaluated and compared with BHA using ß-carotene bleaching assay, DPPH assay and Rancimat method. Phenolic contents of ethanolic extracts of herbs were high compared to their aqueous extracts. The ethanolic extracts showed more antioxidant activity (ß-carotene-linoleic acid model system) than their aqueous counterparts. In DPPH system also, ethanolic extracts were superior to that of aqueous extracts. The ethanolic extracts of the herbs were more effective in preventing the development of the peroxide value and conjugated diene in ghee compared to their aqueous extracts. Ethanolic extracts of herbs showed the higher induction period as compared to their aqueous counter parts in the Rancimat. Antioxidant activity of the herbs decreased in the order vidarikand > ashwagandha > shatavari. Thus, the ethanolic extract of vidarikand was having the maximum antioxidant activity among all the herbs.

Physical Stability and HPLC Analysis of Indian Kudzu (Pueraria tuberosa Linn.) Fortified Milk.

Functional foods provide health benefit beyond basic nutrition. Functional foods fortified with plant ingredients are well known. Ayurveda (Indian System of Medicine) has found several ways in which the medicinal benefits of herbs can be conveyed via certain foods as carriers. Milk is one such carrier which has been effectively used to deliver phytochemicals for targeted health benefits. Indian Kudzu or Pueraria tuberosa Linn. (Fabaceae) is an important medicinal plant of Ayurveda, and experiments suggest that it enhances the health benefits of milk when taken with milk as a carrier. Different milk combinations with P. tuberosa were prepared by homogenizing pasteurized toned milk with its ethanolic and hot water extracts and their stability with reference to pH and coagulation was studied over a period of 15 days. The combinations were also analyzed for puerarin, the major isoflavone C-glucoside present in P. tuberosa, through high-performance liquid chromatography using photo diode array detector. It was observed that there was no precipitate formation and the pH also did not change during the study period indicating their physical stability under the experimental conditions. Also there was no significant change in the content of puerarin during the study period, thereby indicating the chemical stability of the samples. These studies will be useful for developing milk nutraceuticals fortified with Indian Kudzu which has the potential to be included as an ingredient in health and functional foods.

Storage related changes in ghee-based low-fat spread.

In order to assess the shelf life of a low fat spread (LFS) based on ghee, the product with (PS) and without (CS) added 0.05 % (w/w) preservative potassium sorbate and packaged in 200 g polystyrene tubs was stored at 5 °C and evaluated for changes in sensory, physico-chemical and microbiological properties. On the basis of flavour score, the PS spread could be stored for 10 weeks without appreciable loss in quality as against the CS spread which could be stored only for 5 weeks. From the point of view of spreadability, body and texture and colour, the CS product was acceptable even after 11 weeks of storage. Use of preservative had an inhibitory effect on the development of free fatty acids (FFA) and thiobarbituric acid (TBA) reactive substances. While both the products showed an increasing tendency to whey off during storage, CS wheyed off more than PS. The two spreads showed similar oiling off, which increased slightly during the storage. Microbiologically, the ghee-based low fat spreads with and without preservative was stable for 9 and 3 weeks, respectively, from the view point of yeast and mould growth; but the preservative had little effect on the total viable count. Coliforms were absent in all the samples in fresh and during storage.

A comparative study of kinetic and connectionist modeling for shelf-life prediction of Basundi mix.

A ready-to-reconstitute formulation of Basundi, a popular Indian dairy dessert was subjected to storage at various temperatures (10, 25 and 40 °C) and deteriorative changes in the Basundi mix were monitored using quality indices like pH, hydroxyl methyl furfural (HMF), bulk density (BD) and insolubility index (II). The multiple regression equations and the Arrhenius functions that describe the parameters' dependence on temperature for the four physico-chemical parameters were integrated to develop mathematical models for predicting sensory quality of Basundi mix. Connectionist model using multilayer feed forward neural network with back propagation algorithm was also developed for predicting the storage life of the product employing artificial neural network (ANN) tool box of MATLAB software. The quality indices served as the input parameters whereas the output parameters were the sensorily evaluated flavour and total sensory score. A total of 140 observations were used and the prediction performance was judged on the basis of per cent root mean square error. The results obtained from the two approaches were compared. Relatively lower magnitudes of percent root mean square error for both the sensory parameters indicated that the connectionist models were better fitted than kinetic models for predicting storage life.

Galactooligosaccharides: novel components of designer foods.

Since introduction of functional foods, commercialization of the traditionally used probiotics has ushered in more followers into the new fraternity of sophisticated, health-conscious consumers. In 1995, this was followed by the first introduction of prebiotics. Prebiotics are defined as "a non-digestible feed supplement, beneficially affecting the host by selectively stimulating growth and/or activity in one or a limited number of bacteria in the colon." The number of new product introductions with prebiotics has steeply increased over the last few years. Paradoxically, probiotics have limited applications as these cannot be used in wide range of food products because of their viability issue. Fortunately, prebiotics do not suffer from any such constraint and can be used in a wide range of food products. Probiotics do not have a long shelf life in their active form. In most cases, refrigeration is required to maintain the shelf life. While probiotics are predominantly used in fermented dairy products, the use of prebiotics has expanded into other food categories. Prebiotics have successfully been incorporated in a wide variety of human food products such as baked goods, sweeteners, yoghurts, nutrition bars, and meal replacement shakes. For instance, the introduction of galacto-oligosaccharides (GOS) into baby foods has been very successful. GOS, which are identical to the human milk oligosaccharides, has emerged with strong clinical support for both digestive and immune health. Various aspects related to GOS such as types and functions of functional food constituents with special reference to GOS, their role as prebiotics, and enhanced industrial production through microbial intervention are dealt in this review.