The effect of mixed culture fermentation of Saccharomyces cerevisiae and Saccharomyces cerevisiae var. diastaticus on fermentation parameters and flavor profile.

Belgian Saisons and Lambics are two well-known examples in the brewing industry of mixed fermentations, combination of two or more yeast and/or bacteria strains. The purpose of this study was to determine the impact different pitch rates of Saccharomyces cerevisiae (traditional brewing yeast) and S. cerevisiae var. diastaticus (a variant associated with Belgian styles) had on the fermentation kinetics and concentration of the volatile compounds in the finished beers. A series of brews were performed utilizing ratios of S. cerevisiae and diastaticus. The fermentations were heavily monitored, and a model was used to fit fermentation variables. It was found that mixed fermentations produced behaviors that were predictable and proportional to the mixture ratios. As expected, the pure cultural fermentations of diastaticus had a slower fermentation midpoint (M) at 45.45 h versus 28.28 h for S. cerevisiae with the mixed ones falling in between the two. Flavor and aroma play a key role in the acceptability of beer. The mixed fermentations showed a combination of the two different yeast strains aromatic profiles. When combined, there was a strong linearity between alcohols (R2  = 0.94), esters (R2  = 0.89), and the overall total (R2  = 0.91) volatile compounds. PRACTICAL APPLICATION: Modeling is a widely utilized tool in several different fields. The purpose of this research is to apply modeling techniques to describe the fermentation speed and flavor profile of a mixed fermentation between S. cerevisiae and diastaticus. The equations from this data can be used by brewers for product development purposes to make beers with certain flavor profiles within a desired timeframe.

Palatability of Horse Treats: Comparing the Preferences of Horses and Humans.

Despite its importance to product development, few data compare preferences for horses with human consumers. The objectives of this research were to compare treat preferences of horses against horse owners. Product A was a disk-shaped cinnamon-flavored flax-based treat, and product B was a textured apple-flavored oat-based treat. Horses were presented with two treat products in a paired preference test which comprised separate olfaction and consumption periods. Consumers evaluated the treats separately for purchase intent as well as hedonic testing of sensory attributes. No difference was observed for first product sniffed, consumed, or finished during the horse preference test. However, moderate positive correlations were observed between first product sniffed and consumed (P = .01, ф = 0.40) as well as first product consumed and finished (P < .01, ф = 0.48). Horse owners rated product A lower in appearance, texture, size, and purchase intent (P < .01) than product B. These results indicate that consumer testing for animal food should be considered during product development.

Alterations to metabolically active bacteria in the mucosa of the small intestine predict anti-obesity and anti-diabetic activities of grape seed extract in mice.

Epidemiological and clinical studies suggest that grapes and grape-derived products may reduce the risk for chronic disease. Grape seed extract specifically has been gaining interest due to its reported ability to prevent weight gain, moderate hyperglycemia, and reduce inflammation. The purpose of this study was to examine the long-term effects of two doses of grape seed extract (10 and 100 mg kg-1 body wt per d in mice) on markers of metabolic syndrome in the context of a moderately high-fat diet. After 12 weeks, the lower dose of grape seed extract was more effective at inhibiting fat gain and improving glucose tolerance and insulin sensitivity. Neither the high fat diet nor grape seed extract altered skeletal muscle substrate metabolism. Most interestingly, when examining the profile of metabolically active microbiota in the mucosa of the small intestine, cecum, and colonic tissue, grape seed extract seemed to have the most dramatic effect on small intestinal tissue, where the population of Firmicutes was lower compared to control groups. This effect was not observed in the cecal or colonic tissues, suggesting that the main alterations to gut microbiota due to flavan-3-ol supplementation occur in the small intestine, which has not been reported previously. These findings suggest that grape seed extract can prevent early changes in glucose tolerance and alter small intestinal gut microbiota, prior to the onset of skeletal muscle metabolic derangements, when grape seed extract is consumed at a low dose in the context of a moderately high fat diet.

Comparison of two extraction techniques, solid-phase microextraction versus continuous liquid-liquid extraction/solvent-assisted flavor evaporation, for the analysis of flavor compounds in gueuze lambic beer.

Lambic is a beer style that undergoes spontaneous fermentation and is traditionally produced in the Payottenland region of Belgium, a valley on the Senne River west of Brussels. This region appears to have the perfect combination of airborne microorganisms required for lambic's spontaneous fermentation. Gueuze lambic is a substyle of lambic that is made by mixing young (approximately 1 year) and old (approximately 2 to 3 years) lambics with subsequent bottle conditioning. We compared 2 extraction techniques, solid-phase microextraction (SPME) and continuous liquid-liquid extraction/solvent-assisted flavor evaporation (CCLE/SAFE), for the isolation of volatile compounds in commercially produced gueuze lambic beer. Fifty-four volatile compounds were identified and could be divided into acids (14), alcohols (12), aldehydes (3), esters (20), phenols (3), and miscellaneous (2). SPME extracted a total of 40 volatile compounds, whereas CLLE/SAFE extracted 36 volatile compounds. CLLE/SAFE extracted a greater number of acids than SPME, whereas SPME was able to isolate a greater number of esters. Neither extraction technique proved to be clearly superior and both extraction methods can be utilized for the isolation of volatile compounds found in gueuze lambic beer.

Characterization of the polyphenol composition of 20 cultivars of cider, processing, and dessert apples (Malus × domestica Borkh.) grown in Virginia.

Polyphenols and maturity parameters were determined in 20 apple cultivars with potential for hard cider production grown in Virginia, U.S.A. Concentrations of five classes of polyphenols were significantly different across cultivar for both peel and flesh. Total polyphenol concentration ranged from 0.9 µg/g wwb in flesh of Newtown Pippin to 453 µg/g wwb in peel of Red Delicious. Harrison, Granny Smith, Rome, Winesap, and Black Twig cultivars contained the highest concentration of total flavan-3-ols in flesh, indicating potential to impart desired astringency and bitterness to cider under processing conditions where extraction of polyphenols from peel is minimal. These results can inform selection of fruit juice, extracts, and byproducts for investigations of bioactivity and bioavailability of polyphenols, and provide baseline data for horticultural and processing research supporting the growing hard cider industry in Virginia. Based on these data, cultivars Harrison, Granny Smith, Rome, Winesap, and Black Twig show high potential for cider production in Virginia.

Oligomeric cocoa procyanidins possess enhanced bioactivity compared to monomeric and polymeric cocoa procyanidins for preventing the development of obesity, insulin resistance, and impaired glucose tolerance during high-fat feeding.

There is interest in the potential of cocoa flavanols, including monomers and procyanidins, to prevent obesity and type-2 diabetes. Fermentation and processing of cocoa beans influence the qualitative and quantitative profiles of individual cocoa constituents. Little is known regarding how different cocoa flavanols contribute to inhibition of obesity and type-2 diabetes. The objective of this study was to compare the impacts of long-term dietary exposure to cocoa flavanol monomers, oligomers, and polymers on the effects of high-fat feeding. Mice were fed a high-fat diet supplemented with either a cocoa flavanol extract or a flavanol fraction enriched with monomeric, oligomeric, or polymeric procyanidins for 12 weeks. The oligomer-rich fraction proved to be most effective in preventing weight gain, fat mass, impaired glucose tolerance, and insulin resistance in this model. This is the first long-term feeding study to examine the relative activities of cocoa constituents on diet-induced obesity and insulin resistance.