The fluorodinitrobenzene (FONB), succinic anhydride (SA), dansyl chloride (DAN), dye-binding lysine (OBL), total lysine (TL), ninhydrin (NIN) and Tetrahymena lysine (TET) methods were compared for their ability to assess available lysine in soyaprotein heated in the absence or presence of glucose, lactose or xylose and in formaldehyde-treated lactalbumin. The reactive lysine methods showed comparable sensitivity to lysine damage in soyaprotein heated in the absence of sugar, the results indicating the presence of acid labile isopeptides and unidentified acid stable derivatives. Results for soyaprotein heated with glucose, lactose or xylose showed that the type of sugar and the extent of heat treatment has a strong influence on the progress of the Maillard reaction. Furthermore since fructoselysine (F-L) and lactulosyl-lysine (L-L) are colourless up to 30% loss of available lysine can occur without any change in product colour. The FONB method is the most sensitive for mildly damaged glucose-soya samples followed by DAN or OBL, SA and TL whereas for mildly damaged lactose-soya samples the order is OBL, FONB, SA, TL and DAN. For severely damaged samples the DAN or SA methods were the most sensitive followed by OBL, FONB and TL. Formylation of lactalbumin occurred more readily at higher formaldehyde concentrations. Exposure time had less effect while pH (5 and 9) had no effect. Methylene derivatives reached maximum levels sooner than the methylol compounds. Lysine and tyrosine but not histidine formed methylene bridges while tyrosine was found to condense with free formaldehyde during acid hydrolysis raising questions as to the interpretation of similar studies reported in the literature. The FONB, OBL and DAN methods were all very sensitive to this type of damage with the NIN and TL methods being less sensitive and the SA method being completely unsuitable. The TET assay is unsuitable for 'early' Maillard damage since at low sample-N levels growth is stimulated by its ability to utilise unavailable F-L and L-L while at higher N-levels growth is inhibited. No single method is most suitable for all types of damage. Furthermore, all except DAN and DBL are either too long, rather complicated, require expensive equipment or involve the use of dangerous chemicals. The DAN method appears promising but the problem of converting arbitrary fluorescence units to lysine values needs to be overcome. The DBL is recommended for routine analysis since it is simple, economical and highly sensitive to all lysine damage provided care is taken to optimise dye-binding for each type of material analysed. / Thesis (Ph.D.)-University of Natal, Pietermaritzburg, 1985.

Since no effect on CP and diet type on the optimal Trp-to-Lys ratio (TLR) was found in two previous experiments, two extra experiments were planned. In the first one, piglets were fed a Lys-deficient basal diet supplemented with crystalline Lys (to create graded levels of SID Lys). GFR and PUN were measured every 5-d for 15-d; and were analyzed using the broken-line analysis to determine the Lys requirement. As SID Lys level increased, GFR increased linearly and PUN decreased linearly. The SID Lys requirement for was estimated to be 1.02%. To determine the optimal TLR, pigs were fed Trp-deficient basal diet supplemented with crystalline Trp (to create graded levels of SID TLR). Most of the parameters evaluated failed (P > 0.10) to yield an estimate. Based on the evidence we suggest that the optimal SID TLR for early-weaned pigs fed a wheat-barley diet lies below 17.75%.

Since no effect on CP and diet type on the optimal Trp-to-Lys ratio (TLR) was found in two previous experiments, two extra experiments were planned. In the first one, piglets were fed a Lys-deficient basal diet supplemented with crystalline Lys (to create graded levels of SID Lys). GFR and PUN were measured every 5-d for 15-d; and were analyzed using the broken-line analysis to determine the Lys requirement. As SID Lys level increased, GFR increased linearly and PUN decreased linearly. The SID Lys requirement for was estimated to be 1.02%. To determine the optimal TLR, pigs were fed Trp-deficient basal diet supplemented with crystalline Trp (to create graded levels of SID TLR). Most of the parameters evaluated failed (P > 0.10) to yield an estimate. Based on the evidence we suggest that the optimal SID TLR for early-weaned pigs fed a wheat-barley diet lies below 17.75%.

Thesis (M.S.)--University of Kentucky, 2008. / Title from document title page (viewed on February 2, 2009). Document formatted into pages; contains: ix, 146 p. : ill. (some col.). Includes abstract and vita. Includes bibliographical references (p. 138-145).

Thesis (M.S.)--University of Wisconsin--Madison, 1970. / eContent provider-neutral record in process. Description based on print version record. Includes bibliographical references.

Thesis (Ph. D.)--University of Missouri-Columbia, 1999. / Typescript. Vita. Includes bibliographical references (leaves 96-98). Also available on the Internet.

Thesis (Ph. D.)--University of Missouri-Columbia, 1999. / Typescript. Vita. Includes bibliographical references (leaves 96-98). Also available on the Internet.

Thesis (Ph. D.)--University of Wisconsin, 1966. / Typescript. Vita. eContent provider-neutral record in process. Description based on print version record. Includes bibliographies.

Thesis (Ph.D.)--University of Nebraska-Lincoln, 2006. / Title from title screen (site viewed May 23, 2007). PDF text: 231 p. : ill. ; 7.97Mb UMI publication number: AAT 3237598. Includes bibliographical references. Also available in microfilm and microfiche formats.

Wheat-derived products provide the basic nutrition for more than a billion of people in the world (about 40% of humankind). Humans consume more proteins from wheat than from any other source. However, the nutritional quality of wheat proteins is limited by the low content of lysine, one of the essential amino acids that we should incorporate through the diet. As part of this thesis work, we obtained transgenic wheat lines expressing the CI-2 gene from barley under the control of a promoter that is specific for endosperm. This gene has a high content of lysine, an essential amino acid in which wheat proteins are naturally deficient. These transgenic wheat lines have an improved nutritional quality because of the higher content of lysine of their proteins. Bread-making quality of wheat is determined by the number and type of high molecular weight (HMW) subunits of glutenins. The higher the number of HMW subunits of glutenins of a particular wheat variety, the better its bread-making quality. The HMW subunits of glutenins are very polymorphic (there are many different alleles or alternative forms of genes) and some types of subunits are associated with good bread-making quality while others confer a poor quality. The two HMW subunits of glutenins associated with the best bread-making quality in wheat are 1Dx5 and 1Ax1. HMW subunits of glutenins confer elasticity to the dough because of their particular spring shape.Dough with high elasticity are ideal to make bread. Using genetic engineering, we transformed (genetically modified) a commercially available variety of wheat to increase the number of HMW subunits of glutenins from 5 to 6 by introducing an extra HMW subunit known as 1Ax1, which caused an increase of 21% in the content of glutenin compared to the controls. In addition, we over-expressed 1Ax1 in a variety of wheat that already had this subunit by introducing extra gene copies of 1Ax1, which increased the content of 1Ax1 by 44% in this transgenic wheat variety compared to non-transgenic wheat control. Likewise, we over-expressed the HMW subunit of glutenin 1Dx5 causing an increase of 140% in the level of this subunit and a 20% increase in the total content of glutenin. Interestingly, the over-expression of the HMW subunits of glutenins 1Ax1 or 1Dx5 in some of the transgenic wheat lines induced the inactivation of few or all of the endogenous genes that codify for HMW subunits. This phenomenon is part of a mechanism that plants use to inactivate alien genes as a protection against viruses. As expected, these silenced transgenic wheat lines had very low levels of HMW subunit of glutenin and a very poor bread-making quality. However, these lines showed exceptional good quality for making other products such as cookies, crackers, and pizza.