Measurement of lysine damage in proteins heated with gossypol

Anti-nutritional factors and technological processes may modify the nutritional quality of plant proteins. Heated rapeseed meal, soybean, and lupine proteins dried by various processes were used to compare in vivo methods of nutritional quality measurement such as protein efficiency ratio and true digestibility (TD) to in vitro methods such as pH-stat giving degree of hydrolysis (DH) and digestion cell giving nitrogen digestibility (ND). Combined methods taking into account amino acid score were as follows: PDCAAS (protein digestibility-corrected amino acid score) derived from TD, NDCAAS (nitrogen digestibility-corrected amino acid score), and DHCAAS (degree of hydrolysis-corrected amino acid score). Correlations (p < 0.001) were 0.81 (TD vs DH) and 0.88 (TD vs ND). PDCAAS was significantly (p < 0.001) correlated with DHCAAS or NDCAAS (r = 0.92 and 0.98, respectively). Time-consuming and expensive TD determination could be supplanted by both in vitro methods; DHCAAS and NDCAAS could replace PDCAAS. Keywords: Plant proteins; nutritional protein value determination; in vivo methods; in vitro methods; combined methods; correlation between several methods

Section: Discussionmentioning

confidence: 99%

In Vivoandin VitroDigestibility of Soybean, Lupine, and Rapeseed Meal Proteins after Various Technological Processes

Rozan

Lamghari

Linder

et al. 1997

“…These authors also found that defatted cottonseed flour processed to remove gossypol has a PER value near that of casein. Anderson et al (1984) measured lysine damage in protein treated with gossypol. They found that the reduction of in vivo digestibility of cottonseed flour, egg white, and ovalbumin due to gossypol treatment explained the differences observed between the values for chemically reactive lysine measured in vitro from rat growth assays (Feggeros et al, 1992).…”

Section: Nutritional Values Of Different Food Sourcesmentioning

confidence: 99%

Nutritional Value of Proteins from Different Food Sources. A Review

Friedman

1996

744

447

The nutritional value or quality of structurally different proteins varies and is governed by amino acid composition, ratios of essential amino acids, susceptibility to hydrolysis during digestion, source, and the effects of processing. To optimize the biological utilization of proteins, a better understanding is needed of the various interrelated parameters that influence their nutritive value. This review attempts to contribute to this effort. It discusses methods used for protein quality evaluation, research needs to facilitate labeling foods for protein quality, and factors influencing protein quality including amino acid analysis, digestion, food processing, antinutrients, and protein-energy relationships. Recent studies on the nutritional quality of more than 50 common and uncommon protein sources including cereals, legumes, other seeds, meat, seafood, insects, leaves, mushrooms, and potatoes are reviewed. Also described are advantages of consuming low-quality proteins fortified with essential amino acids, nutritional benefits of mixtures of complementary protein sources, plant genetic approaches to improving the nutritive value of foods, problems associated with liquid diets for adults and infants, socioeconomic aspects of new protein foods, and the influence of protein type and quality on lactation, the immune system, and serum lipids. This integrated overview is intended to stimulate interest in the introduction and use of new protein sources for feeding the ever-growing world population.

“…A mixture of Pronase and kidney microsomal peptidases has been used to indicate the extent of Maillard reactions and to prepare hydrolysates in which lactuloselysine and fructoselysine were identified following storage of ultrahigh-temperature processed milk (Moller et al, 1977 a,b). Anderson et al (1984) reported a correlation between results from in vitro digestion with Pronase and in vivo digestibility of proteins heated in the presence of gossypol. However, their method required release of free lysine, and therefore the assays consistently underestimated the in vivo digestibilities.…”

Section: Discussionmentioning

confidence: 98%

Effects of alkali treatment and heat treatment in the presence of fructose on digestibility of food proteins as determined by an immobilized digestive enzyme assay (IDEA)

Chung¹,

Swaisgood²,

Catignani³

1986

An immobilized digestive enzyme assay (IDEA) system composed of two bioreactors, one containing pepsin and the other trypsin, chymotrypsin, and intestinal mucosal peptidases, was used to assess changes in protein digestibility resulting from alkali treatment or heat treatment in the presence of fructose. The degree of amino acid racemization and the amount of lysinoalanine (LAL) formed due to alkali treatment were determined. A linear correlation (r = 0.84) was obtained between loss of digestibility and the sum of the effects of both LAL formation and racemization. The effect of Maillard reactions on both digestibility, as measured with the IDEA system, and available lysine also was assessed. A linear correlation (T = 0.87) between loss of digestibility and loss in available lysine was obtained. These data indicate that the IDEA system is quite sensitive to protein modifications resulting from alkali treatment or Maillard reactions and may be a good predictor of in vivo digestibilities of processed proteins.