Geoffrey W. Smithers

Whey proteins as functional food ingredients

Putative anti-cancer activity of whey proteins has been investigated in an animal model to evaluate their potential role in disease prevention, and to contribute to a basis for their inclusion as ingredients in functional foods. Animal feeding trials have compared the efficacy of dietary whey proteins in retarding chemically induced colon cancer in a rat model of the disease. Dairy proteins, in particular whey protein, were found to be efficacious in retardation of colon cancer in young rats compared with other dietary proteins (meat, soy). The influence of dietary whey protein on development of colon cancer in mature rats has also been examined. Results similar to those with younger animals have been demonstrated, a finding that suggests age does not significantly alter the outcome. Efficacy of whey protein fractions has also been assessed. Preliminary results suggest that diets supplemented with lactoferrin or with β-lactoglobulin enhance protection against the development of putative tumor precursors (aberrant crypts) in the hind gut wall. The mechanism behind the apparent anti-cancer activity of dietary whey proteins in these studies may be related to their sulfur amino acid content, for which there is a high requirement in the rat, and hypothesised role in protecting DNA in methylated form. In a parallel study, a number of potential functional foods containing whey protein (flavored milk, pasta, ice cream, dessert pudding, muesli, and savory dip) have been developed in preparation for human clinical trials. The foods containing whey protein were generally highly acceptable in taste trials. These products are expected to be suitable as delivery vehicles for dietary whey protein in studies aimed at substantiating the human health benefits of this protein source.

Milk-derived growth factors as serum supplements for the growth of fibroblast and epithelial cells

SummaryWe have investigated the response of several epithelial and fibroblastic cells to a mitogenic extract of bovine milk. Cation exchange chromatography was used to produce a mitogen-rich fraction from an industrial whey source that, although comprising only 0.5% of total whey protein, contained the bulk of the growth factor activity. This fraction was a source of potent growth promoting activity for all mesodermal-derived cells tested, including human skin and embryonic lung fibroblasts, Balb/c 3T3 fibroblasts, and rat L6 myoblasts. Maximal growth of all these cell types exceeded that observed in 10% fetal bovine serum. Feline kidney and baby hamster fibroblasts and Chinese hamster ovary cells were less responsive, achieving a maximal growth response of 50–75% that observed in 10% fetal bovine serum. Maximal growth achieved in whey-extract-supplemented cultures of Balb/c 3T3 and human skin fibroblasts, and L6 myoblast cultures exceeded that seen in response to recombinant acidic or basic fibroblast growth factor, platelet-derived growth factor, insulin-like growth factor, or epidermal growth factor. Importantly, addition of low concentrations of fetal bovine serum to the whey-derived mitogenic fraction produced an additive response. However, concentrated milk-derived factors were found to be inhibitory to the growth of all epithelial lines tested, including rat intestinal epithelial cells, canine kidney epithelial cells, and mink lung cells. It is concluded that industrial whey extracted in this form constitutes an important source of potent growth-promoting agents for the supplementation of mesodermal-derived cell cultures.

Modulation of immune responses by bovine |[beta]|-casein

The present study reports the influence of bovine β‐casein on in vitro and in vivo immune responses. Bovine β‐casein showed an inhibitory effect on ovine neutrophil chemotaxis but had an enhancing effect on superoxide production by neutrophils. In response to mitogenic stimulation, the proliferative response of both T and B lymphocytes was significantly enhanced by β‐casein. While β‐casein had no significant effects on IFNγ production by ovine blood lymphocytes, and TNFα production and MHC Class II antigen expression by ovine bronchoalveolar macrophages, it enhanced IL‐1β production by the macrophages. β‐casein also had no influence on bovine NK cell activity against a virally‐infected cell line. Interestingly, β‐casein was found to reduce the adjuvant effect of matrix immune stimulating complexes (ISCOM) on anti‐ovalbumin antibody response in mice when given intramuscularly. Taken together, the results suggest that bovine β‐casein had selective modulating effects in vitro on both innate and adaptive immune responses in ruminants, whereas systemic administration of β‐casein, that might have a depressive effect on adjuvant activity, requires further study.

Waste management and co-product recovery in red and white meat processing

Publisher Summary This chapter discusses the key issues associated with the overall management of waste resulting from the processing of red (beef, sheep) and white (chicken, pig) meat. It also covers various aspects of best practice in the management of such waste, including its minimization, its disposal in an environmentally responsible manner, and approaches to value addition to the waste – including the manufacture of key co-products for application in the food, biotechnology, medical, and related industries. There are drivers and modern approaches for minimization of waste material and maximization of efficiencies in the processing of red and white meat. Enhancements in processing efficiency and minimization of waste can lead to a range of positive benefits for the meat processor, including: a reduction in manufacturing costs and resultant increase in profitability; cost savings on raw materials and energy; reduced environmental pollution; reduced waste disposal and treatment costs; improved workers health and safety; diminished need for end-of-pipe solutions; and an enhanced image for the company and industry. While meat cuts represent the most significant primary product from an abattoir, by- and co-products such as hides, bone, blood, fat, and offal are also generated via the animal slaughtering process. The chapter also highlights the co-product component recovery, derived from both blood and non-blood sources, in meat waste processing.

Comparison of immunomodulatory properties of purified lactoferrin, lactoperoxidase and β-casein in sheep

Bovine milk contains a variety of proteins and peptides that are biologically active (Ogra & Ogra, 1978; Duncan & McArthur, 1981; Newby et al . 1982; Juto, 1985; Stoeck et al . 1989; Mincheva-Nilsson et al . 1990; Watson, 1990; Barta et al . 1991; Politis et al . 1991; Fiat et al . 1993). Our laboratory has a long-term interest in some purified milk proteins, particularly lactoferrin (LF), lactoperoxidase (LP) and β-casein (β-CN), which have been shown to be immunologically significant. Some of our recent studies on these bovine milk proteins, particularly β-CN, indicated that their in vitro immunological effects did not always parallel their in vivo activities (Wong et al . 1996 a , b ; 1997 a , b ). This study was designed to investigate and compare the capacity of these purified bovine milk proteins to modulate a range of components that are vital to in vivo immune responses in sheep, with a view to providing further information on their potential in biomedical applications. To achieve this objective, a sensitive lymphatic cannulation model was employed that allows in vivo immune components and their functions to be measured in lymph collected under physiological conditions.

A Potent Growth Factor Supplement For Cell Culture Purified From Whey

We developed a single-step cation-exchange process for enriching growth factors present in cheese whey. Whey-derived growth factor extract (WGFE) contained only 0.5% whey protein, but all the growth factor activity. It stimulated the growth of mesodermal-derived cells and inhibited epithelial cells. Maximum growth of fibroblasts exceeded the response to serum, whereas other lines, such as CHO cells and L6 myoblasts, required the presence of low serum concentrations (1% v/v) to achieve similar growth rates. Specific assays detected IGF-I and -II, FGF-1 and -2, PDGF, and TGF-s1 and -s2 at concentrations that partially account for the growth-promoting activity. A combination of these growth factors could not reproduce the maximum effect of WGFE, suggesting the presence of other growth factors. Membrane Ultrafiltration of WGFE partitioned and concentrated growth factors, producing fractions enriched in IGF or TGF-s peptides, with enhancement of potency by up to 30-fold. WGFE as a source of growth factors, has application as a serum supplement or extender, particularly for fibroblasts and other mesodermal-derived commercially important cell lines.