Optimizing the orosensory properties of model functional beverages: the influence of novel sweeteners, odorants, bitter blockers, and their mixtures on (+)-catechin.

Unlabelled: The use of flavor-modifying strategies are important to improving the sensory profile of some excessively bitter and astringent functional ingredients, such as (+)-catechin (CAT). Two bitter blockers (ß-cyclodextrin [CYCLO], homoeriodictyol sodium salt [HED]), two sweeteners (sucrose [SUC], rebaudioside A [REB]), and two odorants (vanillin [VAN], black tea aroma [TEA]) were assessed for their efficacy at modifying the bitterness and astringency of CAT in model aqueous solutions. The intensity of oral sensations elicited by CAT was determined in duplicate in binary, ternary, and quaternary mixtures of these stimuli by a trained panel (n = 15) using a 15 cm visual analogue scale.

Carbohydrate refeeding after a high-fat diet rapidly reverses the adaptive increase in human skeletal muscle PDH kinase activity.

Pyruvate dehydrogenase (PDH) regulates oxidative carbohydrate disposal in skeletal muscle and is downregulated by reversible phosphorylation catalyzed by PDH kinase (PDK). Previous work has demonstrated increased PDK activity and PDK4 expression in human skeletal muscle following a high-fat low-carbohydrate (HF) diet, which leads to decreased PDH in the active form (PDHa activity) and carbohydrate oxidation. The purpose of this study was to examine the time course of changes in PDK and PDHa activities with refeeding of carbohydrates after an HF diet in human skeletal muscle.

Detection thresholds for 2-isopropyl-3-methoxypyrazine in Concord and Niagara grape juice.

2-isopropyl-3-methoxypyrazine (IPMP) is the compound responsible for the off-flavor known as ladybug taint, which occurs when Harmnonia axyridis beetles become incorporated with the grapes during juice processing. It is also an important grape-derived component of juice flavor in some varieties. The main objective of this study was to determine the orthonasal (ON) and retronasal (RN) detection thresholds for IPMP in juice.

Determination of ortho- and retronasal detection thresholds for 2-isopropyl-3-methoxypyrazine in wine.

2-Isopropyl-3-methoxypyrazine (IPMP) is a grape-derived component of wine flavor in some wine varieties as well as the causal compound of the off-flavor known as ladybug taint (LBT), which occurs when Harmonia axyridis beetles are incorporated with the grapes during juice and wine processing. The main objective of this study was to obtain robust estimates of the orthonasal (ON) and retronasal (RN) detection thresholds (DTs) for IPMP in wines of differing styles. The ASTM E679 ascending forced choice method of limits was used to determine DTs for 47 individuals in 3 different wines--Chardonnay, Gewürztraminer, and a red wine blend of Baco Noir and Marechel Foch.

The acute effects of differential dietary fatty acids on human skeletal muscle pyruvate dehydrogenase activity.

Pyruvate dehydrogenase (PDH) is an important regulator of carbohydrate oxidation during exercise, and its activity can be downregulated by an increase in dietary fat. The purpose of this study was to determine the acute metabolic effects of differential dietary fatty acids on the activation of the PDH complex (PDHa activity) at rest and at the onset of moderate-intensity exercise. University-aged male subjects (n = 7) underwent two fat-loading trials spaced at least 2 wk apart.

Effect of extracellular osmolality on cell volume and resting metabolism in mammalian skeletal muscle.

The purpose of the present investigation was to establish an in vitro mammalian skeletal muscle model to study acute alterations in resting skeletal muscle cell volume. Isolated, whole muscles [soleus and extensor digitorum longus (EDL)] were dissected from Long-Evans rats and incubated for 60 min in Sigma medium 199 (1 g of resting tension, bubbled with 95% O(2)-5% O(2), 30 +/- 2 degrees C, and pH 7.4).

Endothelin-1 expression in vascular adventitial fibroblasts.

Endothelial cells are a major source of endothelin (ET)-1, but the possibility that vascular adventitial fibroblasts generate ET-1 has not been explored. We hypothesized that aortic adventitial fibroblasts have the ability to produce ET-1, which may contribute to extracellular matrix synthesis. Vascular adventitial fibroblasts were isolated from mouse aorta and incubated with various concentrations of angiotensin II (ANG II).

Antibodies as probes of cytochrome oxidase structure and function.

Antibodies have been raised in rabbits against whole beef heart cytochrome oxidase and against purified subunit V. Western blot analysis showed that antioxidase was largely composed of anti-II and anti-IV antibodies but some anti-I and antibodies against small subunits were elicited. Similar analysis of anti-V showed it to be relatively specific against subunit V.