DEVELOPMENT OF EDIBLE FILMS FOR APPLICATION IN PROBIOTIC GLUTEN FREE AND FERMENTED DAIRY PRODUCTS

Abstract

Probiotic food products effectively confer multiple health benefits to the consumers and promote overall good health. The high demand for healthy, functional foods containing probiotics leads to new ideas and inventions for developing new food products. Several techniques like freeze-drying and spray drying are widely used to maintain bacterial viability to develop new probiotic food products during food processing. Apart from these techniques, edible films are emerging, simpler and inexpensive methods to carry the probiotics and safely deliver them to different food matrices. The developed probiotic edible film prepared from sodium caseinate and supplemented with chia mucilage has been successfully demonstrated for delivering the probiotic cells on bakery products. Chia mucilage has been incorporated in the edible film as a protectant, and the effect of chia mucilage on the survival of probiotics Lactobacillus fermentum NKN51 and Lactobacillus brevis NKN52 embedded in the edible film has been studied. The effect of adding chia mucilage and probiotic cells on the physical and mechanical properties of the developed probiotic edible film has been determined. Chia mucilage significantly enhanced the probiotics’ survival in edible film during the storage at room temperature and 4°C. Supplementation of chia mucilage leads to reduced solubility and improved flexibility due to the interaction between mucilage polysaccharides and the protein of the film matrix.Fourier transform infrared spectroscopy was done to study the interaction between mucilage and film matrix. Microscopic analysis using Scanning electron microscope analysisand Atomic force microscopy revealed the intact microbial cells embedded in the sodium caseinate-based edible film, indicating the protective effect of chia mucilage and protein-based film matrix. The developed probiotic edible film has been applied to the wheat bun and stored at room temperature and 4°C to determine the shelf life of the probiotic edible film. Our study showed the successful application of probiotic edible film as a carrier of probiotics in developing functional bakery products. Another application of developed sodium caseinate-based edible film as a ready-to-go culture strip for developing fermented dairy products has been extensively studied. This study used plant seed mucilages like chia seed and basil seed mucilage as protectants. Starter cultures Streptococcus thermophilus, Lactobacillus bulgaricus, Leuconostoc mesenteroides,and Lactobacillus acidophilus have been incorporated in edible film subjected for the storage stability study during storage at 4°C. Plant seed mucilages significantly enhanced the viability of starter cultures in edible film during storage. The protective effect of plant seed mucilages has been compared with commercial prebiotic fructooligosaccharides on the survival of L.mesenteroides inoculated in sodium caseinate solution. Microscopic analysis was done to visualize the bacterial cells embedded inside the edible film and revealed the intact bacterial cells. The culture strip was prepared by cutting the pieces 2 square centimeters, dipping them in the milk, and kept for incubation to prepare the curd. Light microscopy was done to visualize the starter culture released from the culture strips during milk curdling. Our study reported edible film's novel application as a starter culture carrier for a fermented dairy product like curd. Also, it promoted the use of plant seed mucilages as a protectant for maintaining bacterial survival in stress conditions. The probiotic edible film has been explored in developing the probiotic gluten-free millet-based bread. Developing probiotic bakery products is challenging as probiotics’ viability is affected by the processing steps involved in baking. The increasing number of gluten intolerants resulted in high demand for developing more varieties of gluten-free products. Millets are gluten-free and contain a rich nutritional profile. Finger millet and barnyard millet have been used to develop gluten-free bread. Chia seed flour has been incorporated into the formulation as a gluten alternate.The sourdough mixture was prepared from millet mixture and probiotics L. fermentum NKN51. The effect of incorporating sourdough on bread quality and flavor has been observed. Developed gluten-free millet-based bread was coated with a developed probiotic edible coating to convert the bread into probiotic gluten-free millet-based bread. Moisture loss in probiotic edible coating and its shelf life was studied. Our study developed the novel probiotic gluten-free millet-based bread and showed the application of developed probiotic edible coating on gluten-free bakery products.