Starch is second most abundant biomaterial available after cellulose but the intensity of research on starch is less compared to cellulose. It is a carbohydrate based polymer synthesized in plants for the storage of the energy. Major percentage of starch is being utilized by food industries as raw material for giving texture, flavor, gelling, fat replacement etc. and also has multiple applications in different area due to its biological origin and properties. Native starch possesses low shear stress, poor thermal properties and less digestion resistance and retro-gradation. Thus, it has to be modified using physical, chemical, enzymatic and/or genetic treatments. Physical and chemical modifications using ultrasound and acid hydrolysis is time-efficient and effective process. These economical treatments are predominant for production of digestion resistant starch with increased shelf-life and thermal properties. Ultrasound assisted acid hydrolyzed starch (potato) exfoliates the native starch and modifies the structural arrangement. On acid treatment the amorphous nature of starch converted to crystalline nature. The physical and structural properties of the native starch were enhanced. The digestibility and structure of the modified starch effects on the double helices structure of starch. The size of the starch particle was changed from 1596 nm (Conventional) to 80 and 42 nm on ultrasonication and acid hydrolyzed ultrasonication approaches respectively. The crystallite of the particles was evaluated from XRD analysis. From TEM analysis the starch nanoparticles were found to have spherical morphology.

Efficient reconstitution followed by fermentation of nonfat (skimmed) dry milk is one of the most important aspects in manufacturing of various dairy products. As a first stage, dry milk is normally being reconstituted using conventional approaches such as heating and stirring the mixture. Nevertheless, we demonstrated, that low-frequency (22 ± 1.65 kHz) ultrasound can be used as an alternative to the traditional methods of milk recovery. Low-frequency ultrasound was applied during pre-fermentation stage to improve the dispersity of the resulting milk product and to create good conditions for a post-ultrasound bacterial fermentation of milk. The applied ultrasound power was set in the range of 60-120 W/L. For the fermentation process we used: kefir fungi, fermenter of direct inoculation for yogurt LYOBAC YOYO and mixed culture for kefir LAT LC K. The effectiveness of ultrasound treatment was evaluated based on the accumulation of exopolysaccharides (EPS), vitamin C content, as well as antioxidant activity of the resulting milk product. The effect of ultrasound on microflora and the role of the specific types of bacteria such as Lactobacillus on the accumulation of biologically active compounds in the fermented milk products was studied with use of electron microscopy and MALDI - to FMS method. Overall, our results showed that reconstitution of dry milk with use of ultrasound improves further accumulation of biologically active compounds and rises the nutritional quality of the fermented product.

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