Physicochemical, microbial, and sensory properties of yogurt supplemented with nanopowdered chitosan during storage

Abstract

This study was carried out to determine the possibility of adding nanopowdered chitosan (NPC) into cholesterol-reduced yogurt to improve the functionality of yogurt and the effects of adding NPC on the physicochemical, microbial, and sensory properties of the products during storage. The pH values and mean lactic acid bacteria counts of NPC-added (0.3 to approximately 0.7%, wt/vol) and cholesterol-reduced yogurt ranged from 4.19 to 4.41 and from 4.75 x 10(8) to 9.70 x 10(8) cfu/mL, respectively, when stored at 4 degrees C for 20 d, thereby indicating a possibility of prolonging the shelf life of yogurt. In color, the a* and b* values for cholesterol-reduced yogurt were not significantly influenced by the addition of NPC (0.1 to approximately 0.7%, wt/vol); however, the L* values significantly decreased with the addition of the greatest concentration (0.7%, wt/vol) of NPC at 0-d storage. The sensory test revealed that the astringency scores significantly increased at 0-d storage when the greatest concentration (0.7%, wt/vol) of NPC was added into cholesterol-reduced yogurt. Based on the data obtained from the current study, it is concluded that concentrations (0.3 to ~0.5%, vol/vol) of NPC could be used to produce an NPC-added and cholesterol-reduced yogurt without significantly adverse effects on the physicochemical, microbial, and sensory properties.

Microbial and Physical Properties of Probiotic Fermented Milk Supplemented with Lentil Flour

“…No correlation was found between the pH at the end of storage and the buffering capacity of the medium (R2 < 0.1) nor with the viable counts at the beginning of storage (R2 = 0.26). These data are in line with other studies which show that acidification during storage does not necessarily parallel CFU counts (Seo, Lee, Chang, & Kwak, 2009). According to Kailasapathy, Harmstorf, & Phillips, 2008, the higher the buffering capacity of the media, the smaller the change in pH due to changes in acid content of the food system.…”

Charge related astringency of chitosans

“…Another limitation to the use of chitosan as a food additive is the astringency of chitosans (Rodríguez, Albertengo, Vitale, & Agullo, 2003). Increases in astringency are found in applications such as a nano-chitosan particles (Seo, Chang, Lee, & Kwak, 2011;Seo, Lee, Chang, & Kwak, 2009), whereas astringency was not increased in strawberries coated with a chitosan-based edible film (Han, Lederer, McDaniel, & Zhao, 2005).…”

Comparison of Nanopowdered and Powdered Peanut Sprout-Added Yogurt on its Physicochemical and Sensory Properties during Storage

“…Nanosized ascorbatesolubilized chitosan increases the bioactivity in yogurt and milk (Seo et al, 2009;Seo et al, 2011). Further nanosize calcium supplementation in milk enhances the bone calcium metabolism in ovarirectomized rats (Park et al, 2007).…”