Influence of commercial inactivated yeast derivatives on the survival of probiotic bacterium Lactobacillus rhamnosus HN001 in an acidic environment

Use of Different Nutrients to Improve the Fermentation Performances of Lactiplantibacillus pentosus OM13 during the Production of Sevillian Style Green Table Olives

The aim of this study was to evaluate the fermentation performance of the commercial starter Lactiplantibacillus pentosus OM13 with four nutrients (A, B, C, and D) that differed in the following ingredients: starch, sugars, maltodextrin, inactivated yeast, inactivated yeast rich in amino acids, inactivated yeast rich in mannoproteins, and salt (NaCl). For this purpose, six different experimental productions of Nocellara del Belice table olives were carried out. During transformation, the fermentation process was monitored by measuring pH and plate counts for lactic acid bacteria (LAB), yeasts, Enterobacteriaceae, Staphylococcaceae, and Pseudodomondaceae populations. At the end of the production process, each trial was subjected to volatile organic compound analysis and sensory evaluation. The addition of the different nutrients resulted in a significant reduction in pH (around 2.5 points) after 3 days of fermentation. At the same time, a significant increase in the number of LAB populations (> 6.6 log CFU/mL) was observed for all trials. Volatile organic compound (VOC) analysis revealed the presence of 39 compounds. In this study, nutrient C was optimal for improving the fermentation activity of L. pentosus OM13. These results provide elements for the implementation of experimental protocols to reduce product losses and improve sensory characteristics.

Biovalorization of Market Surplus Bread for Development of Probiotic-Fermented Potential Functional Beverages

Bread wastage is a growing concern in many developed countries. This research aimed to explore the biovalorization of market surplus bread for the development of probiotic-fermented beverages in a zero-waste approach. Bread slurries with different initial total solid contents were inoculated with probiotics Lacticaseibacillus rhamnosus GG (LGG) and Saccharomyces cerevisiae CNCM I-3856, alone and in combination. Our results showed that, of all percentages tested, 5% (w/w, dry weight) initial total solid content resulted in better growth of the probiotics and higher cell counts, while the texture of bread slurries with concentrations higher than 5.0% was too thick and viscous for bread beverage developments. In addition, the development of probiotic-fermented bread beverages was feasible on various types of bread. Furthermore, food additives (sweetener and stabilizer) did not affect the growth of LGG and S. cerevisiae CNCM I-3856 in both mono- and co-culture fermentation. During shelf life measurement, co-inoculation of LGG with S. cerevisiae CNCM I-3856 significantly improved the survival of LGG compared to the mono-culture at 5 and 30 °C, demonstrating the protective effects provided by the yeast. Our study suggests the potential of using market surplus bread as raw materials to deliver live probiotics with sufficient cell counts.

Recent innovations in the production of selected specialty (non-traditional) beers

Customer demand for product diversity is the key driving force for innovations in the brewing industry. Specialty beers are regarded as a distinct group of beers different from two major types, lagers and ales, without established definitions or boundaries. Specialty beers, including low- to no-alcohol beer, low carbohydrate beer, gluten-free beer, sour beer, probiotic beer, and enriched beer, are exclusively brewed and developed keeping in mind their functionality, the health and wellbeing of the consumer, and emerging market trends. Compared with conventional beer-brewing, the production of specialty beers is technologically challenging and usually requires additional process steps, unique microorganisms, and special equipment, which in turn may incur additional costs. In addition, the maintenance of quality and stability of the products as well as consumer acceptability of the products are major challenges to successful commercialization. A harmonious integration of traditional brewing practices and modern technological approaches may hold potential for future developments. In the present review, latest developments in the fermentative production of selected specialty beers are discussed.

Enhanced lactic acid bacteria viability with yeast coincubation under acidic conditions

The enhancing effects of yeasts on the viability of lactic acid bacteria (LAB) under acidic conditions were investigated. Meyerozyma guilliermondii, coaggregative with both LAB strains under acidic conditions, significantly enhanced the viability of Lactobacillus pentosus and L. paracasei in pH 3.0 lactic acid (LA) buffer at 10°C (p < 0.05). Non-coaggregative yeasts (Saccharomyces cerevisiae, Schizosaccharomyces pombe, and Cyberlindnera saturnus) also significantly enhanced the LAB viability (p < 0.05), and physical contact between LAB and yeasts was not essential for the viability-enhancing effect, indicating that the coaggregation had no relation to the enhancing mechanism. Although yeast metabolites and LA assimilation had no enhancing effect, hydrogen peroxide (H₂O₂) decreased after yeast coincubation, and H₂O₂ elimination improved L. pentosus viability. H₂O₂ elimination alone did not sufficiently improve L. paracasei viability, but the addition of antioxidants was effective. These results suggest that the antioxidant activity of yeast increased the LAB viability under acidic conditions.