Drawing upon the capacity of pyruvate to detoxify H2O2, we demonstrate that pyruvate (i) protects against H2O2-dependent, hydroxyl radical-mediated degradation of isolated DNA; (ii) reduces the amount of 8-hydroxy-2-deoxyguanosine detected following oxidative injury to isolated DNA and (iii) diminishes the amounts of detectable hydroxyl radical generated by a H2O2-dependent system. Compared to mannitol, pyruvate protects weakly against oxidative degradation of DNA induced by a H2O2-independent, hydroxyl radical-generating system. The protective effects of pyruvate against H2O2-instigated DNA damage were also evinced in cells in culture exposed to H2O2. In contrast to its protective effects against H2O2-dependent injury to DNA, pyruvate failed to offer convincing protection to another intracellular, H2O2-vulnerable target, glyceraldehyde-3-phosphate dehydrogenase. The protection conferred by pyruvate to intracellular H2O2-vulnerable targets is thus influenced by the nature of the target exposed to H2O2. Pyruvate was markedly protective in a model of cytotoxicity induced by the concomitant depletion of cellular glutathione and inhibition of catalase activity; pyruvate can thus function as an intracellular antioxidant and in this latter model, no evidence of DNA damage was observed. Pyruvate, in contrast to catalase, is a potent protector against cytotoxicity induced by organic peroxides, a finding that cannot be explained by the scavenging of organic peroxides, differences in glutathione content or attenuation in oxidative injury to DNA. We conclude that while DNA damage is a key pathogenetic event in oxidative stress induced by H2O2, such nuclear changes may not universally subserve a critical role in models of H2O2-dependent cell death. We also conclude that the antioxidant capabilities of pyruvate extend beyond scavenging of H2O2 to include potent protection against cytotoxicity induced by organic peroxides.

Concerns about fossil fuel depletion and the environmental effects of greenhouse gas emissions have led to widespread fermentation-based production of bioethanol from corn starch or sugarcane. However, competition for arable land with food production has led to the extensive investigation of lignocellulosic sources and waste products of the food industry as alternative sources of fermentable sugars. In particular, whey, a lactose-rich, inexpensive byproduct of dairy production, is available in stable, high quantities worldwide. This review summarizes strategies and specific factors essential for efficient lactose/whey fermentation to ethanol. In particular, we cover the most commonly used strains and approaches for developing high-performance strains that tolerate fermentation conditions. The relevant genes and regulatory systems controlling lactose utilization and sources of new genes are also discussed in detail. Moreover, this review covers the optimal conditions, various feedstocks that can be coupled with whey substrates, and enzyme supplements for increasing efficiency and yield. In addition to the historical advances in bioethanol production from whey, this review explores the future of yeast-based fermentation of lactose or whey products for beverage or fuel ethanol as a fertile research area for advanced, environmentally friendly uses of industrial waste products.

Two lactose-consuming diploid Saccharomyces cerevisiae strains, AY-51024A and AY-51024M, were constructed by expressing the LAC4 and LAC12 genes of Kluyveromyces marxianus in the host strain AY-5. In AY-51024A, both genes were targeted to the ATH1 and NTH1 gene-encoding regions to abolish the activity of acid/neutral trehalase. In AY-51024M, both genes were respectively integrated into the MIG1 and NTH1 gene-encoding regions to relieve glucose repression. Physiologic studies of the two transformants under anaerobic cultivations in glucose and galactose media indicated that the expression of both LAC genes did not physiologically burden the cells, except for AY-51024A in glucose medium. Galactose consumption was initiated at higher glucose concentrations in the MIG1 deletion strain AY-51024M than in the corresponding wild-type strain and AY-51024A, wherein galactose was consumed until glucose was completely depleted in the mixture. In lactose medium, the Sp. growth rates of AY-51024A and AY-51024M under anaerobic shake-flasks were 0.025 and 0.067 h(-1), respectively. The specific lactose uptake rate and ethanol production of AY-51024M were 2.50 g lactose g CDW(-1) h(-1) and 23.4 g l(-1), respectively, whereas those of AY-51024A were 0.98 g lactose g CDW(-1) h(-1) and 24.3 g lactose g CDW(-1) h(-1), respectively. In concentrated cheese whey powder solutions, AY-51024M produced 63.3 g l(-1) ethanol from approximately 150 g l(-1) initial lactose in 120 h, conversely, AY-51024A consumed 63.7 % of the initial lactose and produced 35.9 g l(-1) ethanol. Therefore, relieving glucose repression is an effective strategy for constructing lactose-consuming S. cerevisiae.

To investigate the effect of Maillard reaction (MR) and gastrointestinal digestion (GID) on the antihyperuricemic activity of tuna protein hydrolysate (TPH), hyperuricemia rats were treated with TPH, its MR products (TPH-M) and gastrointestinal digesta (TPH-D) in this work. Although the XO inhibitory activity of TPH-M was higher than TPH, TPH-M exhibited even lower serum-uric-acid-lowering activity than TPH. Additionally, there was no significant (P < 0.05) difference observed in the inhibition of XO activity in vitro and antihyperuricemic activity of TPH and TPH-D, indicated that the antihyperuricemic activity of TPH would not decrease after GID. Additionally, TPH, TPH-M and TPH-D could effectively inhibit XO activity and downregulate XO mRNA expression in vivo, suggesting the mechanisms of antihyperuricemic effect was related to XO inhibitory activity and XO mRNA expression. As a whole, TPH could be a useful functional ingredient against hyperuricemia.Antihyperuricemic effect of tuna hydrolysate and derived products Y. Liu et al. 264

This study aims to obtain the physicochemical properties of hawthorn fruit powder produced using different methods. Two drying methods, hot‐air drying and freeze‐drying, and three grinding methods, mortar grinding, shear pulverization, and jet milling, were applied to obtain the hawthorn fruit powders. The physicochemical properties of the six powders were compared using scanning electron microscopy, X‐ray diffraction (XRD) analysis, and differential scanning calorimetry. The phenolic content analyses were performed using EIS‐MS2 high‐pressure liquid chromatography. The results showed that freeze‐drying and shear pulverization yielded higher content of cyanidin‐3‐galactoside content. Freeze‐drying and jet milling were the most effective for reduction of the hawthorn fruit powder particle size (D50 value 27.81 μm); a higher water solubility index; higher phenolic content, such as chlorogenic acid and hyperoside; and a more natural color, all of which made the powder better for application in functional foods. Different drying and grinding methods did not change the crystal structure of the hawthorn fruit powder fiber. As a result, the superfine grinding of hawthorn fruit powders could be a promising process in manufacturing instant and convenient foods, as well as active pharmaceutical ingredients. Practical applications Superfine grinding is a new technology that can yield powder with excellent surface properties. Ultrafine powder has unique physical and chemical properties, such as good solubility, dispersion, adsorption, and chemical activity, and is an ideal means of food processing. Hot‐air drying in combination with jet milling can significantly improve the fluidity of the powder. However, freeze‐drying in combination with jet milling results in a higher water solubility index (WSI), procyanidin B2, and chlorogenic acid content, and a more uniform and nonseparable mixture. Freeze‐dried powders have smaller particle sizes and larger specific surface areas than hot‐air‐dried powders. The superfine grinding of hawthorn fruit powders could be a promising process in manufacturing instant and convenient foods, as well as active the pharmaceutical ingredients.