RESUMO
This study aimed to prepare a stirred type of fat-free yogurt from enzymatically hydrolyzed potato powder (EHPP) and skimmed milk powder (SMP) without changing its quality and consumer acceptance. The yogurt formulations prepared contained different amount of EHPP 0, 10, 25 and 50% and were stored for 28 days at 4 °C and observed that with increasing substitution ratio, acid production was increased while the viability of lactic acid bacteria was decreased after 28 days of storage at 4 °C. The antioxidant activities (2-Diphenyl-1-picryl-hydrazyl (DPPH) free radical scavenging activity and ferric reducing antioxidant power (FRAP) of the yogurt were increased with increasing EHPP over the storage period. The yogurt formulations having 25 to 50% EHPP has the highest DPPH free radical scavenging activity and FRAP values. Water holding capacity (WHC) was decreased over the storage period with 25% EHPP. The hardness, adhesiveness and gumminess were decreased while no significant change was found in springiness with EHPP addition over the storage period. The rheological analysis showed an elastic behavior of yogurt gels with EHPP supplementation. The sensory results of yogurt containing 25% EHPP have the highest values of taste and acceptance. Yogurt in combination with EHPP and SMP has the higher levels of WHC than non-supplemented yogurt and better stability was recorded during storage. Supplementary Information: The online version contains supplementary material available at 10.1007/s13197-023-05737-9.
RESUMO
The endogenous components of okara can affect the extraction and modification of insoluble dietary fiber (IDF). This study was intended to investigate the effect of extraction and purification of IDFs from okara affected by the endogenous components and composite enzyme Viscozyme® L. After that, the physicochemical, functional, and structural characteristics of IDFs were analyzed. The results showed that with the purification of degreasing, deproteinizing and destarching, Viscozyme® L can accurately act on the cell wall of okara, leading to the increase in specific surface area of IDF and the formation of honeycomb-like structure. In accordance with the X-ray diffraction and Fourier-transform infrared spectrum investigations, relative crystallinity decreased and certain cellulose components were reallocated and changed into soluble dietary fiber. Moreover, the modified IDF showed improved water-holding capacity (10.73-11.59 g/g), oil-holding capacity (5.37-6.60 g/g), and swelling capacity (8.99-12.37 mL/g), leading to improved adsorption capacities of glucose (maximum: 39.60 mg/g), cholesterol (14.54-33.56 mg/g at pH 7; 10.94-19.37 mg/g at pH 2), and cholate and better cation-exchange capacity. The outcomes demonstrated the potential for the acquired IDFs, particularly the high-purity modified-IDFs T3 and T4 , to be exploited as functional fiber components in the food sector. PRACTICAL APPLICATION: This study advances the understanding of the internal mechanism of modified insoluble dietary fiber (IDF) with different purities in okara. The obtained high-purity modified IDF can be employed as a functional fiber raw material in the manufacture of functional foods, and can also be utilized to assist in the treatment of some illnesses due to its well-established in vivo function.