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Whey, obtained mainly from cheese production, has been considered for a long time as a low added value byproduct. It is a highly polluting material with a biological oxygen demand (BOD) of 30,000 to 50,000 mg l−1, and it has been used as a low cost raw material for the production of several commodities (Marwaha and Kennedy, 1988; Garcia-Garibay et al., 1993). Whey production worldwide has for years represented a challenge to find interesting ways for its utilization. During the last 10 or 20 years, it has been difficult to economically dispose of whey, even in developed countries, due to the increase in cheese production and the installation of larger cheese factories. Although whey utilization has been the subject of much research, very few processes have led to economically attractive ways for its utilization. The most successful processes for its utilization are those that have led to the elaboration of products with a high added value. For instance, whey proteins have high nutritional value and very good functional properties, leading to the interest in developing ultrafiltration techniques in order to recover such proteins without losing their functional properties (Trejo-Vázquez et al., 1995). The utilization of whey proteins as food ingredients in many products due to their unique nutritional and functional properties and, even more, due to their bioactive characteristics, has been the driving force for research on the development of new techniques for their concentration, recovery and fractionation. In the present chapter, a review of the most important characteristics of whey proteins, together with the techniques for their separation, is presented. Table 31.1 shows some important biochemical characteristics of major or important whey proteins. [ABSTRACT FROM AUTHOR]

Huitlacoche is a fungus that has been consumed in Mexico since prehispanic times. This Aztec name is given to the galls or tumors that form in corn cobs by the fungus scientifically known as Ustilago maydis. When infection takes place, a great mass of mycelium is formed in different zones in the corn plant. In the end, a great mass of black spores replaces the mycelium, and it is at this stage that the product is consumed as food (Valverde et al., 1995). Laccase (p-diphenol oxygen oxidoreductase, E. C. 1.10.3.2) catalyzes the oxidation of p-hydroxyphenols. Its activity depends on copper, oxidizes o- and p-dihydroxyphenols and compounds such as p-phenylendiamine and syringaldazine to color final products. Laccases differ from p-diphenol oxidases in their ability to hydroxylate monophenols (Walker, 1995; Palmieri et al., 1997). The objective of this work was to isolate, purify and partially characterize (biochemically and physico-chemically) the laccase from U. maydis. [ABSTRACT FROM AUTHOR]

Capsicum species have been the object of different studies (Dorantes et al., 2000; Careaga et al., 2003; Acero-Ortega et al., 2005) in order to determine their antimicrobial activity, the compounds that would be responsible for it, and the microorganisms that could be affected by it, finding that Staphylococcus aureus, Salmonella tiphymurium, Listeria monocytogenes, Pseudomonas aureaginosa and Bacillus cereus are susceptible to inhibition by Capsicum extracts. Some of the active compounds responsible for the inhibitory action are t-cinnamic acid and its derivatives, which are intermediate compounds in phenylpropanoids pathway. Capsicum annuum oleoresins are "generally recognized as safe" (GRAS) by the FDA, and so their use as natural antimicrobials is safe. However, it is important to know through predictive microbiology and modeling the quantitative effect of the Capsicum extracts, the active compounds, and the interactions with other factors such as pH and temperature. One of the food products that has been involved in outbreaks is fresh rennetcurdled cheese, which has a rich nutrient content, a high water activity and low acidity, which make it an adequate culture medium for the growth of a wide variety of bacteria. Some of these bacteria are known to cause food-borne illness, such as Staphylococcus aureus. It has been estimated that consumption of foods contaminated by this microorganism is responsible for 185,060 illnesses, 1,753 hospitalizations and two deaths per year in the United States. In the United Kingdom since 1980, numbers of reported cases have not exceeded 189 per year, although this is only a small percentage of actual cases (Sutherland and Varnam, 2002). S. aureus has also been involved in food-borne diseases in México, especially in the consumption of milk products. Staphylococcal enterointoxication (staphylococcal food poisoning) results from the ingestion of enterotoxins that are synthesized during growth of S. aureus in foods. S. aureus is capable of producing an enterotoxin in conditions such as: water activity >0.85, a range of pH between 4 to 9.8, temperatures from 10 to 48 °C and a good nutrient supply such as that provided by fresh cheese and other milk products (Halpin-Dohnalek and Marth, 1989). [ABSTRACT FROM AUTHOR]