Motoko Ohata

The formation mechanism by yeast of 4-hydroxy-2(or 5)-ethyl-5(or 2 ) -methyl -3 (2H) -furanone in miso

The mechanism of the formation of 4-hydroxy-2(or 5)-ethyl-5-(or 2)-methyl-3(2H)-furanone (HEMF) with yeast under caltivation in a medium containing amino-carbonyl reactants of ribose and glycine was investigated using stable isotopes of the corresponding compounds. It was confirmed that the skeleton of the five-membered ring and the methyl group of the side chain of HEMF was formed from ribose, and that the ethyl group was derived from the glucose metabolite by yeast. The formation of HEMF was confirmed when acetaldehyde as the glucose metabolite and a cell-free extract from yeast were added to the medium containing amino-carbonyl reactants. These results suggest that the role of yeast in HEMF formation is not only to provide the glucose metabolite, but also in combining the amino-carbonyl reactants with the glucose metabolite.

Bioactive Compounds in Meat

Since health-conscious consumers have made functional foods the leading trends in the food industry, efforts have been taken in many countries to develop new functional foods and to establish regulations for functional foods (Arihara, 2004; Dentali, 2002; Eve, 2000; Hutt, 2000). For example, in 1991, the concept of foods for specified health use (FOSHU) was established by the Japanese Ministry of Health and Welfare (Arihara, 2004, 2006b). FOSHU are foods that, based on the knowledge of the relationship between foods or food components and health, are expected to have certain health benefits and have been licensed to bear the label claiming that a person using them may expect to obtain that health use through the consumption of these foods. As of June 2008, 786 FOSHU products have been approved in Japan. Also, in the United States and European countries, markets for functional foods have been expanding rapidly. Chemicals found as natural components of foods that have been determined to be beneficial to the human body in preventing or treating one or more diseases or improving physiological performance are known as nutraceuticals (Wildman, 2000a, 2000b). Numerous food components with such physiological functions have been isolated and characterized (Hasler, 1998). Many vegetables, for example, have been shown to contain a variety of biologically active phytochemicals (Lindsay, 2000). There has been an accumulation of scientific findings regarding the roles of such components in the prevention of diseases. Rapid progress has been made in the development of functional foods based on the results of studies on food components that have positive health benefits other than the normal nutritional benefits (Arihara, 2004; Heasman & Mellentin, 2001). In addition to various nutraceutical compounds found in vegetables (Lindsay, 2000) and milk (Chandan, 2007; Chandan & Shah, 2007), several attractive meatbased bioactive substances have been studied for their physiological properties (Arihara, 2004, 2006b; Williams, 2007). Such substances include conjugated

Functional meat products.

Abstract: Although studies of functional meat products have been limited until recently, it should be possible to develop novel meat products with potential health benefits by increasing or introducing bioactive properties. This chapter initially describes meat consumption and human health, looking at the potential benefits of representative meat-derived bioactive components, such as conjugated linoleic acid, histidyl dipeptides, and L-carnitine. The chapter then goes on to look at the development of functional meat products. It focuses on the possibility of novel functional meat products utilizing meat protein-derived bioactive peptides, probiotics and prebiotics. Along with the scientific basis for peptides and probiotics, the application of these concepts to meat products is emphasized.

Antioxidant activity of fermented meat sauce and isolation of an associated antioxidant peptide.

The present study was carried out to investigate the radical scavenging and antioxidant activities of fermented meat sauce (FMS) against 1,1-diphenyl-2-picrylhydrazyl (DPPH) and the hydroxyl radical (OH-radical), as well as to isolate substances in FMS related to its antioxidant activity. FMS was prepared by mixing ground pork, koji (rice fermented with koji mold such as Aspergillus), and salt, and fermenting for 24weeks. High antioxidant activities against the DPPH radical and the OH-radical in FMS were observed as about 0.55μmolTroloxeq./ml and 61.2%, respectively. DPPH radical scavenging activities were related to time-dependent changes in proteolysis and antioxidant peptides could be generated in FMS by proteolysis. Liquid chromatography-mass spectrometry analysis detected a substance of molecular weight 406.26g/mol from the purified peptide fraction, which showed an extremely high antioxidant activity against the OH-radical that was greater than 90%. This substance was anticipated to be the tripeptide Gln-Tyr-Pro.

Effects of the Amino-Carbonyl Reaction of Ribose and Glycine on the Formation of the 2(or 5)-Ethyl-5(or 2)-methyl-4-hydroxy-3(2H)-furanone Aroma Component Specific to Miso by Halo-Tolerant Yeast

The formation of HEMF[2(or 5)-ethyl-5(or 2)-methyl-4-hydroxy-3(2H)-furanone], the aroma component specific to miso and soy sauce, was promoted by cultivating the halo-tolerant yeast, Zygosaccharomyces rouxii, in a medium including the amino-carbonyl reaction products based on ribose and glycine. The glucose concentration in the medium influenced the HEMF formation by Z. rouxii.

Chapter Five - Bioactive Properties of Maillard Reaction Products Generated From Food Protein-derived Peptides

Food protein-derived peptides are promising food ingredients for developing functional foods, since various bioactive peptides are released from food proteins. The Maillard reaction, which plays an important role in most processed foods, generates various chemical components during processing. Although changes of amino acids or proteins and reduced sugars by the Maillard reaction have been studied extensively, such changes of peptides by the Maillard reaction are still not resolved enough. Since food protein-derived peptides are widely utilized in many processed foods, it deserves concern and research on the changes of peptides by the Maillard reaction in foods during processing or storage. This chapter initially overviewed food protein-derived bioactive peptides. Then, Maillard reaction products generated from peptides are discussed. We focused particularly on their bioactivities.

Odors generated from the Maillard reaction affect autonomic nervous activity and decrease blood pressure through the olfactory system

BACKGROUND Systolic blood pressure (SBP) of rats decreases significantly following exposure to the odor generated from the Maillard reaction of protein digests with xylose. This study identified active odorants that affect blood pressure and demonstrated the mechanism of action. RESULTS Among the four potent odorants that contribute most to the odor of the Maillard reaction sample, 2,5-dimethyl-4-hydroxy-3(2H)-furanone (DMHF) and 5-methyl-2-pyrazinemethanol (MPM) decreased SBP significantly. The earliest decrease in blood pressure was observed 5 min after exposure to DMHF. Application of zinc sulfate to the nasal cavity eliminated the effect. Furthermore, gastric vagal (parasympathetic) nerve activity was elevated and renal sympathetic nerve activity was lowered after exposure to DMHF. CONCLUSION It is indicated that DMHF affects blood pressure through the olfactory system, and the mechanism for the effect of DMHF on blood pressure involves the autonomic nervous system.