Optimisation of a pilot‐scale spray drying process for probiotic yoghurt,using response surface methodology

The influence of drying air temperatures, drying air flow rate and feed flow rate on percentage survival rate (% SR) of starter and probiotic bacteria, moisture content, water activity and colour of probiotic yoghurt powder produced using a pilot‐scale spray dryer was investigated. Optimisation of spray drying conditions was achieved based on the desirability value. Results showed that inlet air temperature, drying air flow rate, feed flow rate and outlet air temperature of 150 °C, 478 m³/h, 2 L/h and 63.3 °C, respectively, were optimal conditions to produce powder that meets quality specifications and with a satisfactory% SR.     

Viability and α‐ and β‐galactosidase activity of Bifidobacterium breve and Lactobacillus reuteri in yoghurt products supplemented with shiitake mushroom extract during refrigerated storage

This study examined the impact of shiitake mushroom extract (ME) on the viability and α/β enzyme activity of Bifidobacterium breve ATCC 15701 and Lactobacillus reuteri DSM20016 in yoghurt during refrigerated storage. The presence of ME significantly enhanced the viability of both strains. L. reuteri DSM20016 exhibited better stability in yoghurt than B. breve ATCC 15701. L. reuteri DSM20016 showed the highest viability in yoghurt samples containing 4% ME, followed by B. breve ATCC 15701, and then control samples. Results suggest that ME can be used as a natural additive to dairy products to improve the growth and viability of L. reuteri DSM20016 and B. breve ATCC 15701 strains.     

Viability of Lactobacillus acidophilus in rice bran‐enriched stirred yoghurt and the physicochemical and sensory characteristics of product during refrigerated storage

This study was aimed at investigating the fortification of probiotic yoghurt with rice bran to increase nutritional properties of the product. The different levels of rice bran (0.3%, 0.6%, 0.9% and 1.2%) were incorporated into milk. The yoghurt samples were produced after pasteurisation, addition of starter culture and 1% Lactobacillus acidophilus suspension (6 × 10⁸ CFU mL^?1) and incubation. During sample storage in refrigerator, the viability of L. acidophilus, viscosity and physicochemical and sensory properties of product were investigated. Rice bran significantly increased the viability of L. acidophilus (P < 0.05). In addition, all probiotic yoghurts incorporating rice bran indicated higher viscosity and acidity and lower pH and syneresis compared to plain yoghurts. Furthermore, increments in rice bran incorporation levels resulted in a reduction in consumers' sample preferences. In general, the addition of rice bran at a suitable level could increase L. acidophilus viability and improve quality attributes of yoghurt.     

Changes in in vitro protein digestion of retort‐pouched pork belly during 120‐day storage

To investigate the effect of long‐term storage on in vitro protein digestion of the retort‐pouched pork belly. The products were stored at 25 °C for 0, 30, 60 and 120 days and digested with pepsin and trypsin at each time point. SDS‐PAGE and LC‐MS‐MS were applied to separate and identify proteins and their digested products. In vitro protein digestibility decreased from 47.7% after 60‐day storage to 25.4% after 120‐day storage for the samples digested by pepsin, and from 63.9% to 45.7% for the samples digested by pepsin and trypsin at corresponding time points. LC‐MS‐MS demonstrated changes in peptide composition and abundance with storage time. Long‐term storage could deteriorate nutritive values of meat products by reducing digestible protein content.