Probiotic Fermented Foods: An Overview

This work aimed to study the effect of adding skim milk powder (SMP) and whey protein concentrate (WPC) to probiotic mozzarella cheese. Pasteurized cow milk was heated to 55 °C and divided into five parts: PMC1 (control), PMC2 (1% SMP), PMC3 (1.5% SMP), PMC4 (1% WPC), and PMC5 (1.5% WPC). After mixing powders in the respective concentrations in the treatments, the milk was cooled to 35 °C, and Bifidobacterium bifidum culture (5%) was added. Proximate analysis, calcium, soluble nitrogen (SN), total Bifidobacterium bifidum count, cheese yield, hardness, and meltability tests were carried out at 0, 14, and 28 days of storage. The mozzarella cheese samples with WPC added had higher acidity, total solids, and protein content than the mozzarella cheese samples with SMP added and the control samples during storage. The addition of WPC led to a significant increase (p < 0.05) in the count of Bifidobacterium bifidum during storage at 5 °C. The cheeses with WPC added had increased meltability, higher hardness, and higher browning on pizza compared to those of the mozzarella cheese with SMP added. A sensory evaluation showed that the addition of WPC increased sensory scores, compared to the addition of SMP. As storage time progressed, there was a significant (p < 0.05) increase in the Bifidobacterium bifidum, meltability, and sensory scores of PMC in all treatments. Full article

Fermented dairy products not only have a long shelf-life but also have beneficial nutritional values. The products are deficient in dietary fiber and certain bioactive compounds. Adding grains to dairy products is a widespread practice to improve the nutritional and economic aspects. In this work, we studied the effect of fermented millet–milk beverages (FMBs) using pearl millet grains and three different dairy by-products (sweet whey, sweet buttermilk, and skimmed milk). A control treatment prepared with water was also manufactured for comparison. Samples were continuously prepared and fermented using a commercial yogurt starter culture (YC-381) containing L. delbrueckii subsp. bulgaricus, Streptococcus thermophilus, and a pure strain of L. paracasei subsp. Paracasei. Four FMBs (water based: WB-FMB, whey based: WHB-FMB, buttermilk based: BMB-FMB, and skimmed milk based: SMB-FMB) were analyzed during cold storage at 4 °C for up to 15 days for chemical, microbiological properties, minerals content, antioxidant properties, glycemic index, and glycemic load on days 1, 8, and 15. The sensory characteristics of the FMBs were also evaluated during cold storage (4 °C/15 days). In general, the progression of acidity was slower in SMB-FMB and WHB-FMB samples during fermentation compared to in the BMB-FMB sample. The longest fermentation time was for the SMB-FBM sample (3 h), while the shortest was for the BMB-FMB sample (1.5 h). Reflecting the good manufacturing practices, all samples were free of coliform, mold, and yeast. No bacterial growth was detected in the WB-FMB sample at days 8 and 15 of storage, while the growth of Lactobacillus spp. and S. thermophilus was significantly higher (9.97 ± 0.01 and 9.48 ± 0.06, respectively) in the BMB-FMB sample compared to in the other three FMBs. The FMBs produced using dairy by-products had more antioxidant properties. All samples were better perceived during sensory evaluation by panelists than the water-based sample, except for the BMB-FMB sample, in which a bitter taste appeared. In the BMB-FMB sample, the proteolytic degree was significantly higher (4.8 ± 0.09) after 3 h of fermentation by about 460% than in the fresh sample. All samples had a low glycemic index and glycemic load. In addition, acidity progression was slower in SMB-FMB and WHB-FMB samples during fermentation and storage compared to the WB-FMB sample. Therefore, it could be recommended that it is more beneficial to prepare fermented millet–milk beverages using dairy by-products and suitable starter cultures under optimal fermentation conditions instead of using water to maximize the nutritional and economic aspects. Full article