Brewing rich 2-phenylethanol beer from cassava and its producing metabolisms in yeast

Effect of Rhodotorula mucilaginosa inoculation on the aroma development of a fermented vegetables simulated system

Fermented vegetables are known for their unique flavors and aromas, which are influenced by the complex microbial processes that occur during fermentation. Rhodotorula mucilaginosa is a red yeast strain that is frequently isolated from fermented vegetables. However, the specific mechanisms underlying their effects on aroma production remain unclear. In this study, a simulated system of vegetables fermented using vegetable juices was used to investigate the effects of R. mucilaginosa inoculation on aroma development. The results demonstrated that this red yeast strain could utilize the nutrients present in the vegetable juices to support its growth and reproduction. Moreover, the inoculation of fermented vegetable juices with this yeast strain led to an increase in the levels of umami amino acids and sweet amino acids. Furthermore, this yeast strain was found able to significantly reduce the content of sulfur-containing compounds, which may decrease the unpleasant odor of fermented vegetables. Additionally, the yeast strain was capable of producing high concentrations of aromatic compounds such as phenylethyl alcohol, methyl 2-methylbutyrate, methyl butyrate, and nonanoic acid in a minimum medium. However, only phenylethyl alcohol has been identified as a core aromatic compound in fermented vegetable juice. The three fermented vegetable juices exhibited significantly different flavor profiles according to comparative analysis. Therefore, the core flavor compounds found in fermented vegetables are primarily derived from the release and modification of endogenous flavors naturally present in the vegetables, facilitated by the yeast during fermentation.

Effects of Processing Methods and Conditioning Temperatures on the Cassava Starch Digestibility and Growth Performance of Broilers

As an important food crop, cassava is rich in nutrients and high in starch content and is widely used in the production of industrial raw materials. However, the utilization value of cassava is limited due to the reduction of planting area and the existence of anti-nutritional factors. Therefore, we evaluated in vitro cassava starch digestibility and in vivo growth performance of broilers in a 3 × 3 factorial arrangement of treatments using three processing methods (mechanical crushing (MC), steam conditioning (SC), and puffing conditioning (PU)) and three conditioning temperatures (60, 75, and 90 °C) to screen for the optimal processing method and conditioning temperature to improve the utilization of cassava. In the in vitro cassava starch digestion study, the digestibility and digestion rate (p < 0.01) were higher at conditioned 90 °C than that at 60 or 75 °C, and PU was higher than SC and MC (p < 0.01) (0.25-2 h). The amylose content and amylose/amylopectin at conditioned 60 °C or PU were lower (p < 0.01) than that of 75 or 90 °C or SC, whereas the opposite was true for amylopectin content (p < 0.01). The resistant starch content of SC or PU was lower (p < 0.01) than MC. In the in vivo study, broilers fed diets conditioned at 60 °C or SC had a lower (p < 0.05) feed-to-gain ratio than those fed diets conditioned at 90 °C or PU diets. The ileum apparent digestibility of starch and AME were higher (p < 0.05) for broilers fed SC diets than for those fed MC diets. These results indicate that cassava starch promoted starch digestion rate by reducing amylose content and amylose/amylose under PU combined with a conditioning temperature of 60 °C, ileum digestibility of starch in broilers fed SC diets was higher than MC diets regardless of conditioning temperature, and SC diets increased AME and decreased F/G to promote growth performance of broilers.

Insights into the metabolic profiling of Polygonati Rhizoma fermented by Lactiplantibacillus plantarum under aerobic and anaerobic conditions using a UHPLC-QE-MS/MS system

Introduction

Polygonati Rhizoma is a multi-purpose food with medicinal uses. Fermentation of Polygonati Rhizoma by lactic acid bacteria could provide new insights into the development of Polygonati Rhizoma products.

Methods

In this study, Lactiplantibacillus plantarum was fermented with Polygonati Rhizoma extracts in a bioreactor under aerobic and anaerobic conditions with pH and DO real-time detection. Metabolic profiling was determined by UHPLC-QE-MS/MS system. Principal component analysis and orthogonal partial least-squares discriminant analysis were used to perform multivariate analysis.

Results

A total of 98 differential metabolites were identified in broth after fermentation, and 36 were identified between fermentation under aerobic and anaerobic conditions. The main metabolic pathways in the fermentation process are ABC transport and amino acid biosynthesis. Most of the compounds such as L-arginine, L-aspartic acid, leucine, L-lysine, citrate, inosine, carnitine, betaine, and thiamine were significantly increased during fermentation, playing a role in enhancing food flavor. Compared with anaerobic fermentation, aerobic conditions led to a significant rise in the levels of some compounds such as valine, isoleucine, and glutamate; this increase was mainly related to branched-chain amino acid transaminase, isocitrate dehydrogenase, and glutamate dehydrogenase.

Discussion

Aerobic fermentation is more beneficial for the fermentation of Polygonati Rhizoma by L. plantarum to produce flavor and functional substances. This study is the first report on the fermentation of Polygonati Rhizoma by L. plantarum and provides insights that would be applicable in the development of Polygonati Rhizoma fermented products.

Physicochemical, Electronic Nose and Tongue, Sensory Evaluation Determination Combined with Chemometrics to Characterize Ficus hirta Vahl. (Moraceae) Beer

Ficus hirta Vahl. (FHV) is widely consumed because of its functional and aromatic compounds. The incorporation of adjuncts contributes to the functional and flavor properties of beers. This study aims to enrich FHV extractions to develop beers with satisfactory physicochemical, antioxidant, and sensory characteristics. As a result, beers with 0.1 g/mL (P1) and 0.067 g/mL (P3) FHV extraction showed the highest values of physicochemical properties including °Brix, antioxidant activity, foam, lightness, and color intensity. Electronic nose and tongue results show that the aroma of P1 and taste of P3 were quite different from those of other FHV beers, resulting in substantially high consumer preference. The liking drivers of FHV beers were color appearance, hop and malty odor, sweet and malty flavor, thickness, and carbonation mouthfeel. However, the astringency flavor attribute was the disliking factor for beers. The results of this study may provide some references and guidelines for the development of Ficus hirta Vahl. functional beer to control the physicochemical, antioxidative, and sensory properties of the beer.

Brewing on an industrial and a craft scale – impact on the physicochemical properties and volatile compounds profile of the pale pilsener-style lager beer analysed with HS/GC-MS

The pale Pilsener-style lager beers produced on a massive and craft scale were taken to analyse their basic physicochemical properties (alcohol content, pH, haze, real degree of fermentation) and volatile compounds profiles. The research was carried out using a beer analyser equipment and a headspace gas chromatography-mass spectrometry method (HS/GC-MS). The findings showed that in terms of physicochemical and flavour attributes, the quality of craft beers differed to a higher degree from the standard Pilsener beer quality than in the case of industrial beers.

Dose-independent genotoxic response in A549 cell line exposed to fungicide Iprodione

The fungicide Iprodione is widely applied in vegetables and raises concern for human health. The A549 human lung carcinoma cell line is a suitable model for assessing the toxicological effects of drugs. The goal of this work was to evaluate the genotoxicity and oxidative stress in the A549 cell line exposed to sublethal concentrations from 3 to 100 µg/mL Iprodione considering LC50 = 243.4 µg/mL Iprodione, as determined by the MTT assay. Generalized Linear Mixed Models (GLMM) were performed to determine the association between the responses NDI, MNi_m and MNi_b and the explanatory variables. Iprodione and solvent were relativized to the control whereas the concentration was included as numeric variable. ANOVA was used for the comparison of treatments. The coefficients of linear association between the explanatory variables and NDI, and the coefficients of logistic association between explanatory variables and MNi_m were not significant. However, these coefficients showed significant association with MNi_b only for Iprodione treatment but not for Iprodione concentration, indicating lack of dose-response relationship. Genotoxicity risk assessment indicated that the increase in Iprodione concentrations increased slightly the probability of belonging to the genotoxic category. ANOVA showed significant differences in MNi_b, and non-significant differences in NDI and MNi_m among treatments. The oxidative stress analysis performed at 3, 12, and 25 μg/mL Iprodione showed a significant and linear increase in SOD, and a significant and linear decrease in GSH and GST. The Dunnett test was significant for GSH at 12 and SOD at 25 μg/mL.