Protein Nutritional Value Research Articles

Association of Bio-energy Processing-Induced Protein Molecular Structure Changes with CNCPS-Based Protein Degradation and Digestion of Co-products in Dairy Cows.

The primary objective of this study was to develop a model to predict Cornell Net Carbohydrate Protein System (CNCPS) protein degradation and digestion based on protein molecular structure changes induced by bio-energy processing in different types of co-products (CoPR, CoPC, CoPS = co-products from bioprocessing of rapeseed, canola seed, and soybean, respectively). The results showed that the inherent structure changes induced by the processing had a close relationship with CNCPS predicted protein degradable, undegradable, and digestible contents. The amide I to II ratio and α-helix to β-sheet ratio could be used to predict total degradable protein (R(2) = 0.99, RSD = 0.84, P < 0.001). Total CNCPS intestinal digestible protein could be predicted by protein structure α-helix to β-sheet ratio (R(2) = 0.93, RSD = 0.33, P < 0.001). In conclusion, the processing-induced protein molecular structure changes were highly linked to protein nutritive value of the co-products and could be used as predictors for CNCPS protein degradation and digestion in dairy cattle.

Uwarunkowania postaw konsumentów wobec produktów mięsnych

Celem artykułu było przedstawienie uwarunkowań postaw konsumentów wobec produktów mięsnych. W szczególności określono ilość i częstotliwość spożywania produktów mięsnych, preferencje i częstotliwość zaopatrywania się w produkty mięsne oraz czynniki mające wpływ na ich zakup i konsumpcję. Na potrzeby artykułu przeprowadzono analizę danych wtórnych oraz pierwotnych, za pośrednictwem wywiadu standaryzowanego. Badania zostały przeprowadzane w 2014 r. na grupie 150 respondentów zamieszkujących Bydgoszcz i jej okolice. Przeciętne spożycie mięsa i jego przetworów wynosi rocznie w Polsce ponad 70 kg na osobę. Najczęściej spożywanym mięsem przez polskich konsumentów jest wieprzowina, rośnie spożycie drobiu, zmniejsza się spożycie wołowiny. Istotną rolę podczas zakupu produktów mięsnych odgrywają takie czynniki, jak wygląd, skład, producent, zawartość tłuszczu i białka oraz walory odżywcze, najmniejsze znaczenie mają działania promocyjne.

EFFECT OF DRYING PROCESSES ON BIOCHEMICAL CONTENTS OF SPIRULINA PLATENSIS AS A PROTIEN SOURCE FOR FISH DIET

The present work aimed at studying the effect of drying temperature on the biochemical contents of Spirulina platensis to choose the best temperature that can be used for drying without affecting its contents to be used as a fish diet, with a good quality, low price and to give the immunity to fish in fish farms. Open air and temperatures (60oC and 120oC) were applied for drying Spirulina platensis. The alga was cultivated on large scale in concrete ponds (25 and 50 m3) to be used as fish meal. The crude protein content of the dried matter in S. platensis biomass was 59.1, 63.2, and 64.8% in case of open air, 60oC and 120oC respectively. Also there are no significant differences measured of amino acids content on open air, 60 oC and 120 oC. The nutritional value of protein is due to its amino acids contents which were of 49 %, 49% and 50% for the dried matter at open air and 60oC and 120oC respectively. Also, the lipid contents, carbohydrates, fibers and ash were 0.74%, 20.78%, 0.18% and 8.8% respectively in open air, 0.78%, 18.9%, 0.22% and 8.8% at 60oC and 0.94%, 19.74%, 0.12% and 9.0% respectively at 120 oC. The results revealed that the concentrations of chemical contents (lipid, carbohydrates, fibers and ash) were higher at 120 oC than those at the other two procedures. The concentrations of crude protein (64.8 %) and amino acids (50%) were also higher at 120 oC. It was found that there is no difference between the three procedures of drying but drying at 120 oC saves time and therefore it is better to be used. Sixteen weeks of feeding was conducted to investigate the effect of fish meal replacement with Spirulina on growth performance and body weight. About 20% increase of weight gain and with highly significant average daily gain 0.450 and 0.546 for diet1 (control) and diet 2 (Spirulina diet) respectively and feed conversion ratio were 1.189 and 1.333 for diet1 (control) and diet 2 (Spirulina diet). The use of the harvested alga S. platensis was to solve the problem of availability as protein source not only as fish feed but also saving aquatic environment.

The Assessment Of Energy And Protein Needs Coverage In Hospitalized Patients: OCENA POKRITOSTI POTREB PO ENERGIJI IN BELJAKOVINAH MED HOSPITALIZIRANIMI BOLNIKI.

AimAiming at assessing sufficiency of energy/protein intake in hospitalized patients, the objective was to monitor and analyze actual food intake of patients hospitalized in three clinical wards of one of major Slovenian hospitals.Methods53 patients were included in the study. Food intake was assessed 3 times daily from leftovers. Nutritional status was assessed with Nutritional Risk Screening tool 2002. The observed outcomes were percentage of energy coverage (PEC) and percentage of protein coverage (PPC). In PEC energy nutritional value of the menu (ENVM), and in PPC protein nutritional value of the menu (PNVM) were considered as the main modifiable risk factors. Data were analyzed univariately and multivariately by using logistic regression method.ResultsThe patients did not cover energy needs (67.4±24.5%). Multivariate model for PEC was highly significant (R2=0.347; pmodel<0.001) with ENVM showing high strength of association (b=0.040; p=0.004). Patients also did not cover protein needs (84.0±40.2%). Multivariate model for PEC was highly significant (R2=0.477; pmodel<0.001) and PNVM showing high strength of association (b=0.937; p=0.002).ConclusionFor successful prevention and early detection of malnutrition, food intake in hospitals is vital and should be constantly monitored. A simple method for monitoring is proposed. The menus provided to patients should also be adequate in terms of energy and protein content.

Conversion of Canola Meal into a High‐Protein Feed Additive via Solid‐State Fungal Incubation Process

AbstractThe study goal was to determine the optimal fungal culture to reduce glucosinolates (GLS), fiber, and residual sugars while increasing the protein content and nutritional value of canola meal. Solid‐state incubation conditions were used to enhance filamentous growth of the fungi. Flask trials were performed using 50 % moisture content hexane‐extracted (HE) or cold‐pressed (CP) canola meal with incubation for 168 h at 30 °C. Incubation on HE canola meal Trichoderma reesei (NRRL‐3653) achieved the greatest increase in protein content (23 %), while having the lowest residual levels of sugar (8 % w/w) and GLS (0.4 μM/g). Incubation on CP canola meal Trichoderma reesei (NRRL‐3653), A. pullulans (NRRL‐58522), and A. pullulans (NRRL‐Y‐2311‐1) resulted in the greatest improvement in protein content (22.9, 16.9 and 15.4 %, respectively), while reducing total GLS content from 60.6 to 1.0, 3.2 and 10.7 μM/g, respectively. HE and CP canola meal GLS levels were reduced to 65.5 and 50.7 % by thermal treatments while solid‐state microbial conversion further reduced GLS up to 99 and 98 %, respectively. Fiber levels increased due to the concentration effect of removing oligosaccharides and GLS.

Cultivo de Trigo harinero Triticum aestivum, una alternativa para la soberanía nutricional y adaptación ante el cambio climático, en el departamento de Jinotega

El presente ensayo, se centró en dar a conocer la importancia agronómica y económica del rubro del trigo harinero Triticum aestivum, como estrategia de Soberanía, Seguridad nutricional local y de Desarrollo Rural en tres zonas climáticamente diferentes del departamento de Jinotega, debido a su alto valor nutricional de proteínas 10.1%, carbohidratos 76.7% y fibras 47.55%, que aporta este rubro a las familias productoras del mundo. Así incluirlo en los programas de gobierno locales para contra restar la pobreza extrema de Nicaragua; y disminuir las importaciones económica de 36.1 millones de dólares que invierte Nicaragua anualmente. Por otro lado, incorporar el trigo harinero en los proyectos de sistemas de producción agrícolas diversificado con enfoque agroecológico para lograr la adaptabilidad ante los impactos del cambio climático.&#x0D;

Red clover (Trifolium pratense L.) draft genome provides a platform for trait improvement.

Red clover (Trifolium pratense L.) is a globally significant forage legume in pastoral livestock farming systems. It is an attractive component of grassland farming, because of its high yield and protein content, nutritional value and ability to fix atmospheric nitrogen. Enhancing its role further in sustainable agriculture requires genetic improvement of persistency, disease resistance, and tolerance to grazing. To help address these challenges, we have assembled a chromosome-scale reference genome for red clover. We observed large blocks of conserved synteny with Medicago truncatula and estimated that the two species diverged ~23 million years ago. Among the 40,868 annotated genes, we identified gene clusters involved in biochemical pathways of importance for forage quality and livestock nutrition. Genotyping by sequencing of a synthetic population of 86 genotypes show that the number of markers required for genomics-based breeding approaches is tractable, making red clover a suitable candidate for association studies and genomic selection.

Evaluation of soil microbial communities as influenced by crude oil pollution

Spirulina platensis, a blue green microalga, has been used since ancient times as a source of food because of its high protein content (65%) and nutritional value. Lipids isolated from S. platensis have been shown to contain high levels of polyunsaturated fatty acids, including linolenic acid which is a precursor of arachidonic acid; this cyanobacteria contains, also, several kinds of sterols. The aim of this study is to evaluate the nutritional quality of S. platensis of Tamenrasset, Algeria. This study shows the analysis of nutritional quality of S. platensis of Tamanrasset, Algeria, to know nutritional value of our local strain. Biochemical analysis was performed for moisture, protein, glucose, lipid and minerals content. The chemical composition is based on the identification of fatty acids, using gas chromatography and quantification of the mineral elements by using the atomic absorption spectrometry (AAS). The results showed that S. platensis of Algeria has an important nutritional quality. Key words: Spirulina platensis, nutritional, quality, proteins, fatty acids.

Seasonal variations in the amino acid profile and protein nutritional value of Saccharina latissima cultivated in a commercial IMTA system

Seaweeds have potential for the provision of biomass for food and feed supplements. The demand is increasing especially for proteins as ingredients; however, the amino acid profile is essential for evaluation of the nutritional value of proteins. The year-round protein concentration and amino acid profiles of Saccharina latissima were determined, and the harvest time and nutritional potential were evaluated. Bi-monthly samples were analyzed from S. latissima (including epiphytes, when present) cultivated commercially at an integrated multi-trophic aquaculture (IMTA) site and a reference site in Denmark in 2013–2014. Overall, there was no significant difference for the tested parameters between the two sampling sites; however, seasonal variations were found. The protein concentration varied markedly reaching a maximum of 10.8 % dry weight (DW) in November and a minimum of 1.3 % DW in May 2013. Aspartic and glutamic acids dominated the amino acid profile, accounting for up to 49 % of the total. Greatest seasonal differences in amino acid composition occurred in July, with leucine contributing most (22.7–26.7 %) of the observed differences. A maximal essential amino acid (EAA) score of 68.9 % (based on WHO/FAO/UNU requirements) was achieved in November 2013. The presence of epiphytes in July to November changed neither the amino acid content nor the EAA score. S. latissima is comparable with wheat as a protein ingredient for fish feed and appears to be a suitable protein/amino acid source for human consumption. This study proposes that there may be a mismatch between harvest time and nutritional value. The preferable harvest time for S. latissima is November, due to high protein content and EAA score. However, higher yield and cleaner biomass for human consumption would be found in May.

Protein Oxidation in Processed Meat: Mechanisms and Potential Implications on Human Health.

Processed meats represent a large percentage of muscle foods consumed in the western world. Various processing steps affect the physicochemical properties of the meat, compromise its nutritional components, or produce some compounds that are of health concern. Hence, the impact of oxidation on human health and the aging process and the influence of diet on these harmful reactions are of growing interest. Past decades have seen more focus on lipid oxidation, microbial deterioration, and pathogenicity, as well as production of carcinogenic compounds during meat processing. The oxidation of protein, which is a major component in meat systems, has received less attention. Protein oxidation has been defined as a covalent modification of protein induced either directly by reactive species or indirectly by reaction with secondary by-products of oxidative stress. Not only are these modifications critical for technological and sensory properties of muscle foods, they may have implications on human health and safety when consumed. Cooking, for example, has been observed to increase free radical generation while it also decreases the antioxidant protection systems in meat, both of which contribute to protein oxidation. Many other meat processing techniques, as well as other emerging technologies, may significantly affect protein oxidation and protein overall quality. This paper explores the current understanding of meat processing techniques and their possible effects on the status of protein oxidation and nutritional value, as well as their possible implications on human health.

Effect of Heating Method on Alteration of Protein Molecular Structure in Flaxseed: Relationship with Changes in Protein Subfraction Profile and Digestion in Dairy Cows.

This study evaluated the effect of heating methods on alteration of protein molecular structure in flaxseed (Linum usitatissimum L.) in relation to changes in protein subfraction profile and digestion in dairy cows. Seeds from two flaxseed varieties, sampled from two replicate plots at two locations, were evaluated. The seeds were either maintained in their raw state or heated in an air-draft oven (dry heating) or autoclave (moist heating) for 60 min at 120 °C or by microwave irradiation (MIR) for 5 min. Compared to raw seeds, moist heating decreased (P < 0.05) soluble protein (SP) content [56.5 ± 5.55 to 25.9 ± 6.16% crude protein (CP)] and increased (P < 0.05) rumen undegraded protein (RUP) content (36.0 ± 5.19 to 46.9 ± 2.72% CP) and intestinal digestibility of RUP (61.0 ± 2.28 to 63.8 ± 2.67% RUP). Dry heating did not alter (P > 0.05) the protein subfraction profile and rumen degradation kinetics, whereas MIR increased (P < 0.05) the RUP content from 36.0 ± 5.19 to 40.4 ± 4.67% CP. The MIR and dry heating did not alter (P > 0.05) the amide I to amide II ratio, but moist heating decreased (P < 0.05) both the amide I to amide II ratio and α-helix-to-β-sheet ratio. Regression equations based on protein molecular spectral intensities provided high prediction power for estimation of heat-induced changes in SP (R2 = 0.62), RUP (R2 = 0.71), and intestinal digestibility of RUP (R2 = 0.72). Overall, heat-induced changes in protein nutritive value and digestion were strongly associated with heat-induced alteration in protein molecular structures.

The Impact of Processing on Amino Acid Racemization and Protein Quality in Processed Animal Proteins of Poultry Origin

Re-authorization of processed animal proteins (PAPs) in EU, derived from by-products of human food production, could increase manufacturing of proteins for feed ingredients and reduce the need of imported proteins mainly of plant origin. The PAPs production is largely done by the rendering process during which authorized animal by-products are heat treated to extract valuable protein and animal fat, ensuring sterilizing conditions of raw incoming materials. Proteins exposure to certain processing conditions induces two important chemical changes, racemization of amino acids and formation of cross-linked amino acid. These changes are associated with appreciable reduction of protein digestibility and nutritional value. The aim of this study was to verify the effect of heat treatment on amino acid racemization in processed animal proteins of poultry origin and related nutritional implications by evaluation of their in vitro digestibility. The results reported confirm the detection of racemized amino acids in processed animal proteins, especially D-aspartic acid, as realistic indicators of thermal treatments during PAP manufacturing. In our results, the severe (115°C) and prolonged heat treatment (180 minutes) revealed a D-Asp content of 28.1%.Prolongation of temperature treatment (20, 30 and 180 min, at 115°C) significantly (P<0.05) affects in vitro protein digestibility, which decrease from 86.0%, in no-treated sample, to 78.3% and 79.1% after 20 and 30 min, respectively, and to 76.3% after 180 min. The processing conditions applied during PAPs preparations and the racemization of proteins amino acids may reasonably be involved in the loss of protein quality.

Nutritive value of canned River Nile Crayfish (Procambarus clarkii) products

This study was carried out to utilize Crayfish (Procambarus clarkii) flesh to produce canned products i.e. control (with or without vegetables). To some extent, raw Crayfish meat contains high contents of protein (15.22%) and fat (1.29%). Canned Crayfish products have a high nutritional quality of protein and high nutritional value as indicated by the values of total indispensable amino acids (TIAAs), Indispensable amino acids index (IAAsI), biological value (B.V.%) and percentage satisfaction of indispensable amino acids upon consuming 150g of the product (P.S./150g%). The (GDR value) grams consumed to cover the daily requirements of indispensable amino acids for adult man were lower. Thermophilic bacteria were not detectable and TBC were within the Egyptian standard specification (E.O.S., 1990). The consumption of 150g (one jar) of canned crayfish product covered the major minerals by about P (80–95%), Ca (72–92%), Mg (47–75%), Na (31–36%) and K (19–24%). Thus, canned Crayfish products under investigation had a high nutritional quality and acceptability as arranged in the following order, canned Crayfish with tomato sauce in green peas (CCP) was the best treatment, followed by canned Crayfish with tomato sauce in green beans (CCB) and canned Crayfish with tomato sauce (control) (CCC).

Characteristic of the nutritive value of the protein from rye coryopses. II. Evaluation of rye grain protein quality by Dye-Binding Capacity method

The usefulness for breeding porposes of the azosulphonic dye-binding capacity (DBC method) by proteins for large scale screening nutritive value characteristic of rye grain protein was studied. It was established that binding capacity of dye by rye grain protein is positively, significantly correlated with protein nutritive value indicators, e.g. CS (Chemical Score). The amounts of the binded dye by 1 g of milled rye grains were positively, significantly correlated with "useful" protein content of grains. DBC plus Kjeldahl protein evaluations are together suitable for mass screening quantitative and qualitative characteristic of rye grain protein.

Protein nutritional value of rocket leaves and possibilities of itsmodification during plant growth

Abstract: Leafy vegetables are an important source of protein and other nutrients. Vegetable protein is characterized by different and variable amino acid composition. This study determined the protein content and amino acid composition of the leaves of garden rocket (Eruca sativa Mill.) as affected by different nitrogen and potassium nutrition regimes. On average, the rocket leaves accumulated 11.7% dry matter, including 16.6% protein. Increased nitrogen rates resulted in a significant decrease in protein content as opposed to increased potassium rates. In the majority of cases, the increasing rates of nitrogen and potassium used in the nutrition of rocket plants significantly modified the amino acid composition of protein, which contained all primary amino acids, both nonessential and essential. In the group of nonessential amino acids, glutamic acid and aspartic acid were predominant. The proportions of all the amino acids determined were substantially lower than in the FAO/WHO reference guidelines. The greatest variation was found in the case of threonine and lysine, while the smallest was for sulfur amino acids. It was shown that the rocket leaves were characterized by a high content of protein with a beneficial amino acid composition, and rocket should be taken into consideration as a diet component. Modifications in the plant nutrition system can be used to increase the amount of rocket protein and to obtain its specific chemical profile.

Relationship of feeds protein structural makeup in common Prairie feeds with protein solubility, in situ ruminal degradation and intestinal digestibility

The objectives of this study were to determine the relationship between the intrinsic molecular structures of protein feeds and protein solubility, in situ rumen degradability and intestinal digestibility. The feeds investigated were barley, corn, oat, wheat, lentil, peas, canola meal, expeller meal (extruded canola meal), soybean meal, mill feeds (pelleted byproducts from cereal grains), lantic sugar beet pulp, blood meal and meat meal. The protein molecular structures were quantified from spectral data on unique bands such as amid I and amide II, and protein secondary structures such as α-helix and β-sheet and their ratios using attenuated total reflectance-Fourier transform infrared molecular spectroscopy (ATR-FTIR). The feeds were analyzed for protein solubility, in situ ruminal degradation and intestinal digestibility. The water-based (10.5–70.3g/100g crude protein (CP)) and buffer-based (4.4–76.3g/100g CP) protein solubility had a large variation among the feeds. The effective ruminal degradability (13.8–77.0g/100g CP), intestinal digestibility of rumen undegraded protein (RUP; 57.0–89.1g/100g RUP) and total protein digestibility (76.1–96.4g/100g CP) had a large variation among the feeds. Significant differences were observed in protein amide I and amide II area, model-fitted α-helix and β-sheet height and in the ratio of amide I to II area. The protein molecular structural characteristics were strongly correlated with protein solubility, ruminal degradation and intestinal digestibility. Amide II area had the highest correlation with the contents of CP (r=0.713), water-soluble CP (r=0.730), buffer-soluble CP (r=0.436) and intestinal digestible CP (r=0.735). Whereas the area ratio of amide I:II showed strong correlation (r=0.707) with the content of rumen degradable CP. The protein amide II area and β-sheet height could be used to predict the contents of intestinal digestible RUP (R2=0.826) and total digestible CP (R2=0.808) of prairie feeds in dairy cattle. This study report a novel data on feed protein molecular structures and showed that protein structural makeup was associated with protein nutritional value and digestive behaviour in dairy cattle.

Pepsin Digestibility and Antioxidant Activity of Egg White Protein in Model Systems with Green Coffee Extract

Model systems of egg white protein and green coffee extract were dry heated at 110 or 180oC for up to 1 h to investigate the extent of interactions between coffee polyphenols and a protein of high nutritional significance. Saccharose, starch, sunflower oil, and ferrous ions were also applied to the model mixtures. In heated and control systems amino acid profiles, in vitro pepsin digestibility, color, and antioxidant properties were analyzed. Among heated samples, high protein nutritional value was obtained in the system containing 3% of green coffee extract, while the least favorable conditions for maintaining protein high nutritional value were observed in system of protein, saccharose, starch, and sunflower oil without addition of coffee polyphenols. The samples of high protein nutritional value were also characterized by high antioxidant activity.

Co-suppression of synthesis of major α-kafirin sub-class together with γ-kafirin-1 and γ-kafirin-2 required for substantially improved protein digestibility in transgenic sorghum

Co-suppressing major kafirin sub-classes is fundamental to improved protein digestibility and nutritional value of sorghum. The improvement is linked to an irregularly invaginated phenotype of protein bodies. The combined suppression of only two genes, γ kafirin-1 (25 kDa) and γ-kafirin-2 (50 kDa), significantly increases sorghum kafirin in vitro digestibility. Co-suppression of a third gene, α-kafirin A1 (25 kDa), in addition to the two genes increases the digestibility further. The high-digestibility trait has previously only been obtained either through the co-suppression of six kafirin genes (α-A1, 25 kDa; α-B1, 19 kDa; α-B2, 22 kDa; γ-kaf1, 27 kDa; γ-kaf 2, 50 kDa; and δ-kaf 2, 18 kDa) or through random chemical-induced mutations (for example, the high protein digestibility mutant). We present further evidence that suppressing just three of these genes alters kafirin protein cross-linking and protein body microstructure to an irregularly invaginated phenotype. The irregular invaginations are consistent with high pepsin enzyme accessibility and hence high digestibility. The approach we adopted towards increasing sorghum protein digestibility appears to be an effective tool in improving the status of sorghum as a principal supplier of energy and protein in poor communities residing in marginal agro-ecological zones of Africa.

Molecular spectroscopic investigation on fractionation-induced changes on biomacromolecule of co-products from bioethanol processing to explore protein metabolism in ruminants

Fractionation processing is an efficient technology which is capable to redesign/redevelop a new food or feed product with a specified chemical and nutrient profile. This processing technique was able to produce four different fractions (called “A”, “B”, “C”, “D” fractions/treatments) with different nutrient profile form a co-product of bioethanol processing [wheat dried distillers grains with soluble (DDGS)]. To date, there is no study on the effect of fractionation processing on inherent molecular structure of different fractions and how the processing-induced structural change affect the metabolic characteristics of protein and nutrient availability. The objectives of this experiment were to: (1) investigate the effect of fractionation processing on changes of protein functional groups (amide I, amide II, and their ratio) and molecular structure (modeled α-helix, β-sheet, and their ratio), and (2) study the relationship between the fractionation processing-induced changes of protein molecular structure and nutrients availability as well as the metabolic characteristics of protein. The hypothesis of this study was that the fractionation processing changes the molecular structure and such changes affect the metabolic characteristics of protein. The protein molecular structure spectral profile of the fractions A, B, C and D were identified by Fourier-transform infrared attenuated total reflection spectroscopy (FT/IR-ATR). The results showed that the fractionation processing significantly affected the protein molecular spectral profiles. The differences in amide I to amide II peak area and height ratios were strongly significant (P<0.01) among the treatment fractions, ranging from 4.98 to 6.33 and 3.28 to 4.00, respectively. The difference in the modeled protein α-helix to β-sheet ratio was also strongly significant (P<0.01) among the treatment fractions. Multivariate molecular spectral analysis with cluster (CLA) and principal component analyses (PCA) showed that there are no clear distinguished clusters and ellipses among the fractions (A, B, C and D) in the protein amide I and II region ca. 1726–1485cm−1. The correlation study showed that the modeled α-helix to β-sheet ratio tended to have a negative correlation with truly absorbed rumen undegraded protein (ARUPDVE: r=−0.944, P=0.056<0.10) and total truly absorbed protein in the small intestine (DVE: r=−0.946, P=0.054<0.10), but there was no correlation between the α-helix to β-sheet ratio and the degraded protein balance (DPBOEB: P=0.267<0.10). In conclusion, the fractionation processing changed the molecular structural spectral profiles in terms of amide I to II ratio and α-helix to β-sheet ratio. These changes negatively affected the metabolic characteristics of protein and true protein supply. These results indicated that spectral features of different fractions could be used as a potential tool to predict true protein nutritive value.

Studies on Brassica carinata Seed. 1. Protein Molecular Structure in Relation to Protein Nutritive Values and Metabolic Characteristics

The objectives of this study were to investigate (1) the protein chemical profile, (2) the protein subfractions partitioned by the Cornell Net Carbohydrate and Protein System (CNCPS), (3) the rumen crude protein (CP) degradation kinetics, (4) the protein supply predicted by the DVE/OEB system, (5) the protein structural features using a Fourier transform infrared (FTIR) spectroscopic technique with attenuated total reflectance (ATR), and (6) the correlations between protein intrinsic structural features and nutritional profiles in three strains of Brassica carinata in yellow and brown seed coats, with comparison to canola seed as a reference. The results showed that carinata seed strains were different in both nutritional values and IR absorbance within the protein spectral region (ca. 1720-1482 cm(-1)). The comparison between yellow and brown B. carinata seeds indicated that the former was lower in acid detergent insoluble crude protein (ADICP; P = 0.002) and undegradable protein fraction (PC; P = 0.002) and greater in the degradable (D) fraction (P = 0.004) and true absorbed protein in the small intestine (DVE; P = 0.02) as well as feed milk value (FMV; P = 0.02) than the latter. The brown canola seed (Brassica napus L.) was also not in full accordance with B. carinata seed on these parameters. The FTIR studies showed significant differences in protein amide II peak height, amide I peak area, and β-sheet height among different B. carinata strains. However, multivariate spectral analyses indicated a similarity in protein structural makeup in these four kinds of oilseed. The not very strong correlations shown in this study implied that the limited sample size and narrow range in biological and spectral variation might be responses for the weak relationships between chemical profile and mid-IR spectral data. Further studies using sufficient samples with wide and diverse range in nutritional properties are needed to illustrate the actual relationship between spectroscopic data and nutritional profiles in oilseeds.