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.

Electrospun Smart Oxygen Indicating Tag for Modified Atmosphere Packaging Applications: Fabrication, Characterization and Storage Stability.

Pack integrity is essential for the success of modified atmosphere packaging of food products. Colorimetric oxygen leak indicators or tags are simple and smart tools that can depict the presence or absence of oxygen within a package. However, not many bio-based electrospun materials were explored for this purpose. Ultraviolet light-activated kappa-carrageenan-based smart oxygen indicating tag was developed using the electrospinning technique in this study and its stability during storage was determined. Kappa-carrageenan was used with redox dye, sacrificial electron donor, photocatalyst, and solvent for preparing oxygen indicating electrospun tag. Parameters of electrospinning namely flow rate of the polymer solution, the distance between spinneret and collector, and voltage applied were optimized using Taguchi L9 orthogonal design. Rheological and microstructural studies revealed that the electrospinning solution was pseudoplastic and the mat fibers were compact and non-woven with an average fiber size of 1-2 microns. Oxygen sensitivity at different oxygen concentrations revealed that the tag was sensitive enough to detect as low as 0.4% oxygen. The developed tag was stable for at least 60 days when stored in dark at 25 °C and 65% RH. The developed mat could be highly useful in modified atmosphere packaging applications to check seal integrity in oxygen devoid packages.

Effect of clove bud and curry leaf essential oils on the anti-oxidative and anti-microbial activity of burfi, a milk-based confection.

With scientific advancement in the field of food science and technology, there has been an increased availability of innovative ingredients that can be utilized towards value addition, quality enhancement, natural preservation, shelf life enhancement and adding novelty to traditional Indian dairy products. Here a scientific attempt has been made to increase the anti-oxidative and anti-microbial potential of burfi, a popular confection of Indian sub-continent with low shelf life using herbal essential oils (EOs) (natural preservative, antioxidant and antimicrobial) such as curry leaf (CRYF) (0.05-0.15 ppm) and clove bud (CLVB) (0.15-0.25 ppm) EO. Samples were subjected to physico-chemical, sensory, anti-oxidant and microbiological analysis and the results revealed that increasing the herbal EOs levels in burfi led to increase in anti-microbial and anti-oxidative attributes but simultaneously decreased the sensory attributes. Physico-chemical attributes remained unaffected upon EOs incorporation. Principal component analysis revealed 81.5% relation between the burfi samples and its quality attributes (DPPH activity, ABTS activity, total phenolic content, sensory attributes, standard plate count, yeast and mould count, moisture content, water activity, lightness, L* value, redness, a* value and yellowness, b* value). Herbal EOs i.e. CRYF@0.10 ppm and CLVB@0.20 ppm on khoa basis were found optimum for incorporation into burfi for enhancing storage stability without compromising the sensory acceptability.

Anti-oxidative, physico-chemical and sensory attributes of burfi affected by incorporation of different herbs and its comparison with synthetic anti-oxidant (BHA).

Six different herbs, viz., turmeric, ginger, clove, curry leaves, basil leaves and small cardamom, were incorporated (@1% of khoa) into burfi, a heat desiccated-sweetened milk product, for their ability to act as natural anti-oxidant and were compared against butylated hydroxyanisole (BHA). Anti-oxidative potential of burfi significantly increased with herbs incorporation, which was in the order of clove > turmeric > basil leaves > curry leaf > ginger > cardamom. However, it was lower when compared to BHA added samples. Gross compositional attributes of burfi remained unaffected upon herb incorporation, however, significant lowering in water activity was observed upon cardamom and clove addition. Hunter color analysis revealed that cloves decreased lightness and increased redness, turmeric increased yellowness, and basil and curry leaves increased greenness in burfi. Texture attributes viz., hardness, springiness and gumminess were significantly higher for clove and cardamom burfi. Sensory evaluation revealed that among the different herbs, cardamom is highly preferred in burfi followed by ginger, turmeric, clove, curry leaves and basil leaves. However, no significant difference in sensory attributes were observed between control, cardamom and BHA added burfi samples.