Abstract

Barley (Hordeum vulgare L.) is ranked fourth amongst the cereals after maize, rice, and wheat and is mostly used for malting and animal feed. The use of barley in processed food products has gained popularity in recent years. The majority of the kernel or more than 70% of its dry weight is made up of starch. The native starch is unstable to a wide range of conditions such as temperature, pH, shear forces, and so on, and thus, limits its usage to a wide range of food and non-food industrial applications. The objective of this study was to modify the starch isolated from two cultivars of barley, i.e., PL-751 and PL-830 using physical (annealing) and enzymatic (amylase) methods and to investigate the differences in functional properties of native and modified starch. The functional properties such as syneresis, light transmittance, swelling, and solubility index changed significantly in modified starches as compared to native starch. The syneresis of annealed starch for PL-751 and PL-830 increased from 85.5%–96.67% and 81.0%–94.50%, respectively. The syneresis values of amylase-treated starch for PL-830 and PL-751 at enzymatic concentration of 7.5 U increased from 86.5%–92.0% and 84.5%–89.83%, respectively. Similarly, the values increased from 88.17%–91.83% and 79.5%–87.5% for PL-830 and PL-751 at 15 U enzymatic concentration, respectively. The light transmittance of annealed starch for both PL-830 and PL-751 decreased significantly (p ≤ 0.05) during storage for 5 days. The swelling and solubility index also increased significantly (p ≤ 0.05) with an increase in temperature both in native as well as modified starch. However, a significant (p ≤ 0.05) drop in swelling and solubility index of an annealed and enzyme-modified starch was observed as compared to native starch. Starch modification is a dynamic field with vast potential for future applications in both the food and non-food industries. The physical and enzymatic modification in starch enhanced the thermal stability, swelling power, and solubility index of the starch with reduced syneresis characteristics resulting in stable gels and a better shelf life. With the help of modification techniques, minimally processed foods can be developed with an increase in consumer demand. Modified starch helps in improving the shelf life of food products by enhancing moisture retention, and inhibiting retrogradation, and thus, the texture and freshness of the product are maintained for a longer period of time.

Key words: Amylase, Annealed starch, Barley, Functional properties, Modified starch, Starch