The in vivo and in vitro protein quality of three hemp protein sources

In this work, the protein quality of defatted hemp hearts and protein-enriched hemp fractions was determined. Protein quality was assessed using a rodent bioassay to evaluate growth and protein digestibility, while amino acid composition was determined via HPLC. A method for determining in vitro protein digestibility was compared to in vivo methodology and used to generate an in vitro protein quality score. The true protein digestibility of hemp protein 2, a hemp protein concentrate, was significantly lower than that of either defatted hemp hearts or hemp protein 1, a hemp protein concentrate (p < .05). While there was no relationship between the in vivo and in vitro measurements of protein digestibility (R 2 = .293, p = .459), there was a significant correlation between the protein digestibility-corrected amino acid score (PDCAAS) determined in vivo and in vitro PDCAAS (R 2 = .989, p = .005). The protein efficiency ratio of hemp protein 1 was significantly lower than that of either defatted hemp hearts or hemp protein 2 (p < .05). These data highlight the nutritional capacity of hemp protein sources while also demonstrating the relationship between in vivo and in vitro methods for determining protein quality.

Sustainable Process for Tortilla Production Using Ohmic Heating with Minimal Impact on the Nutritional Value, Protein, and Calcium Performance

The nixtamalization process used for tortilla production entails extended processing time and generates pollutant effluents. Ohmic heating (OH) is an emerging technology that uses an alternating electric current for rapid and uniform food heating and mitigates effluent concerns. However, gaps exist in nutrient bioavailability studies. In this work, we assessed OH's impact on tortilla nutritional value, protein, and calcium using a rat model. Twenty-five male Wistar rats were fed one of four diets for 21 days: raw corn (RC) as an experimental control, OH-processed tortillas (OHTs), traditionally processed tortillas (TPTs), commercial tortillas (CTs), and a casein diet (CD) as a growth control. Despite similar protein and macronutrient profiles, OH significantly enhanced insoluble fiber content. The weight gain sequence was OHTs > TPTs > CTs > RC. OHTs exhibited superior protein digestibility (88.52%), which was 3% higher than other diets. The serum albumin (2.63-2.73 g/dL) indicated moderate malnutrition due to the tortilla's lower protein content. Nonetheless, the protein efficiency ratio (1.2-1.74) showed no significant difference from TPTs. Bone characteristics and fracture strength resembled the tortilla-fed groups, surpassing RC. X-ray diffraction and scanning electron microscopy confirmed that the OHT and TPT diets improved male rat bone thickness and crystallinity. The findings suggest the potential for OH as an eco-friendly tortilla production method, maintaining nutritional value comparable to traditional methods.

[Protein efficiency ratio of genetically modified pork powder with fat-1 gene]

OBJECTIVE

To evaluate the protein efficiency ratio(PER) of genetically modified pork powder with fat-1 gene(GM group), and thus evaluate whether the nutritional evaluation value of fat-1 gene pork powder has changed.

METHODS

Sixty weaned SD rats(60-80 g) were randomly divided into casein group, parental control group and GM group according to sex and weight, 20 rats in each group, half of each sex. The rats in the three groups were fed with corresponding formulated feed containing 10% protein for 28 days. The body weight and food intake of each group were recorded weekly. Blood was collected at the end of the experiment to determine hematology and blood biochemical indexes. The food utilization rate, organ/body weigh indexes, PER and corrected PER were calculated.

RESULTS

The weight of rats in all groups increased steadily during the experimental period. Statistically significant differences were found in some hematology and blood biochemical indexes and organ/body weigh indexes. No biologically significant changes were found. The food utilization rate of GM group was higher than that of casein group(P<0.05), which was equivalent to that in the parental control group. The PER of both genetically modified pork powder with fat-1 gene and parental white pork powder were higher than that of casein(P<0.05).

CONCLUSION

The PER of genetically modified pork powder with fat-1 gene was equal to that of its parental white pork powder.

Perspective: Assuring the Quality of Protein in Infant Formula

Current regulations require that the assessment of protein quality in infant formula be determined using the protein efficiency ratio (PER) rat bioassay where the growth of rats fed a test protein is compared with the growth of rats fed casein. This review cites authoritative body opinions that the PER is not a preferred method for scoring protein quality, particularly as applied to the infant formula. Methodological recommendations specified by FDA and recent guidance propose to control nonprotein dietary variables in the PER. In contrast, the essential amino acid pattern of human milk has been adopted internationally as the standard for protein quality in infant formula. Because casein, the control protein in the PER fails to meet the standard of human milk essential amino acids, the PER based on casein can generate a false assurance of the quality of protein in an infant formula. FDA should revise the method of demonstrating the quality factor for the biological quality of protein to the essential amino acid pattern of human milk, which would be simpler, conform to international standards, and should be considered by FDA under a new statute. Alternate methods of determination of protein quality can be used selectively when there are questions about the digestibility of new protein sources or the effects of manufacturing processes.

[Protein efficiency ratio of genetically modified corn with Cry1Ab-ma gene]

OBJECTIVE

To evaluate the protein efficiency ratio(PER) of genetically modified corn with Cry1Ab-Ma gene and parental corn.

METHODS

Sixty SD rats(60-80 g) were randomly divided into genetically modified corn group, parental corn group and casein control group, with 20 rats in each group and half male and half female. Casein was added to 10% of the diet in casein control group. When the protein content of the diets in the genetically modified corn group and parental corn group was still less than 10% according to the principle of maximum incorporation, the defective part was supplemented with casein. Rats were free to drink and eat for 28 days. Food intake and body weight of each group were recorded every week. Blood was collected at the end of the experiment to determine hematology and blood biochemical indexes. The main organs were weighed and organ/body weigh indexes were calculated. PER and corrected PER were calculated.

RESULTS

The body weight of all the animals in each group showed an increasing trend, and the weight growth was normal. Although there were statistical differences in the individual indexes of end-stage hematology and blood biochemical indexes, there was no biological significance. There were no significant change in the organ/body weigh indexes. PER of genetically modified corn, parental corn and casein were 2.01±0.22, 1.77±0.30 and 3.64±0.48, respectively. The corrected PER of genetically modified corn and parent corn were 1.38 and 1.22, respectively.

CONCLUSION

The PER of this batch of genetically modified corn with Cry1Ab-ma gene was better than that of parental corn, but worse than that of casein.

Optimal Dietary Protein Requirement for Juvenile Sesarmid Crab (Episesarma singaporense)

Simple Summary

Essential information on the major nutrients which could affect the survival and growth of early juvenile Episesarma singaporense crabs, especially their protein requirements, is still lacking. Therefore, the objective of this study was to determine the dietary protein requirement for early juvenile E. singaporense crabs. Growth performance, feed utilization, digestive enzyme activity, and muscle amino acid profiles were used as criteria for assessing the suitable treatment. Based on our investigations, desirable characteristics were achieved in the crabs fed with diet containing 45% protein. This level is similar to previous reports in other crab species, and could be employed in preparing artificial diets for this species.

Abstract

The optimal dietary protein requirement for sesarmid crabs (Episesarma singaporense) was investigated. Juvenile E. singaporense, individually reared in plastic glasses containing 250 mL sea water, were fed five fish meal-soybean meal-microbound diets variously containing dietary protein levels of 30%, 35%, 40%, 45% and 50% for six weeks. A completely randomized design was used in the experiment, comprising five treatments with 60 crabs in each. At the end of the experiment, a significant improvement in survival was observed in all treatments relative to the diet containing 30% dietary protein (p < 0.05) while the growth performance parameters did not differ across the five dietary groups. A significantly higher protein efficiency ratio was observed in the E. singaporense crabs receiving 45% dietary protein relative to the remaining treatments. The specific activities of the digestive enzymes, pepsin-like, trypsin, amylase, and lipase, and the amylase to trypsin ratio fluctuated across the five treatments, but that of chymotrypsin remained consistent, suggesting different nutritional responses to the various dietary protein levels. The crabs receiving the 45% protein diet had significantly higher in essential amino acid (EAA) profiles followed by the 40% protein diet, although some EAA values were only moderate. The pattern for the non-EAA (NEAA) was reversed, and the ΣEAA/ΣNEAA ratio was higher in the crabs receiving the 45% protein diets relative to the other treatments. Based on our investigations, the optimal dietary protein requirement achieving desirable characteristics of juvenile E. singaporense crabs was 45%. This finding would be a useful guideline in preparing artificial diets for the mariculture of this species.

Thermal processing methods differentially affect the protein quality of Chickpea (Cicer arietinum)

Chickpea is a widely produced pulse crop, but requires processing prior to human consumption. Protein bioavailability and amino acid quantity of chickpea flour can be altered by multiple factors including processing method. For this reason, the protein quality of processed chickpea flour was determined using in vivo and in vitro analyses for processed chickpeas. Processing differentially affected the protein digestibility-corrected amino acid score (PDCAAS) of chickpeas with extruded chickpea (83.8) having a higher PDCAAS score than both cooked (75.2) and baked (80.03). Interestingly, the digestible indispensable amino acid score (DIAAS) value of baked chickpea (0.84) was higher compared to both extruded (0.82) and cooked (0.78). The protein efficiency ratio, another measure of protein quality, was significantly higher for extruded chickpea than baked chickpea (p < .01). In vivo and in vitro analysis of protein quality were well correlated (R 2 = .9339). These results demonstrated that under certain circumstances in vitro methods could replace the use of animals to determine protein quality.

Amino acid availability of protein meals of different quality for adult and growing mink (Neovison vison)

Protein and amino acid (AA) availability of three protein meals of expected different quality were evaluated in young growing and adult mink. Lamb meal (LM), poultry meal (PM) or fishmeal (FM) were used as main protein sources in three extruded diets investigated by determining apparent total tract digestibility (ATTD) and nitrogen balance in 12 growing mink males aged 8-11 weeks in a Latin square design. In adult mink, ATTD of the diets was determined. The diets had lower protein content than recommended for growing mink, protein contributing 23% of total metabolisable energy (ME), to ensure differences in growth response. The LM diet with expected low protein quality revealed lower content of essential AA than the PM and FM diets. The ATTD of major nutrients and essential AA was significantly affected by diet, with the poorest values for LM, intermediate for PM and the highest values for FM. Mink kits revealed lower ATTD values than adults for protein, AA and especially fat, resulting in lower dietary ME content for kits than for adults. The mean difference was greatest for the LM diet with lowest ATTD and smallest for the FM diet with the highest ATTD. Nitrogen retention and growth rate differed significantly among diets and was lowest for diet LM and highest for diet FM, respectively. Different dietary essential AA contents and ATTD, especially of methionine, were the main factors to explain the difference in growth response. Generally, plasma essential AA concentrations did not clearly reflect the different dietary supply and the different growth response. The study shows that a recommended level of 0.31 g apparent total tract digestible methionine per MJ ME covers the minimum requirement with a safety margin. To obtain optimal growth, the lower digestive capacity in young mink kits should be considered when choosing feed ingredients.

The amino acid composition and protein quality of various egg, poultry meal by-products, and vegetable proteins used in the production of dog and cat diets

New protein ingredients are used to support pet food market growth and the development of new products while maintaining animal dietary needs. However, novel protein sources (e.g., spray-dried chicken, and (or) rice, pea, and potato protein concentrates) have limited data available regarding their protein quality. The objective of this study was to evaluate protein ingredients used in the pet food industry by laboratory analysis and a chick growth assay as a model. Following analysis for proximate and amino acid composition, chicks (six birds per pen with four pens per treatment) were fed experimental diets for 10 d. Diets contained 10% crude protein from each of the experimental protein sources (spray-dried egg-SDEG; spray-dried egg white-SDEW, spray-dried inedible whole egg-SDIE, chicken by-product meal-CBPM, chicken meal-CKML, low-temperature fluid bed air-dried chicken-LTCK, low-temperature and pressure fluid bed dried chicken-LTPC, spray-dried chicken-SDCK, whey protein concentrate-WPCT, corn gluten meal-CGML, corn protein concentrate-CPCT, potato protein isolate-PPIS, rice protein concentrate-RPCT, pea protein isolate-PEPI, soy protein isolate-SPIS, and soybean meal-SBML) along with an N-free diet (negative control). Chicks fed SDEG, SDIE, and LTPC had the highest protein efficiency ratio (PER; P < 0.0001; 5.18, 5.37, and 5.33, respectively), LTCK and SDCK were intermediate (4.54 and 4.79), and the CBPM and CKML were the lowest among the poultry proteins for EAA:NEAA, PER, and Lys availability. Among the vegetable proteins, PPIS and SBML had the highest PER values (3.60 and 3.48, P < 0.0001). In general, the chick PER method ranked the quality of animal protein sources higher than vegetable proteins, and these results were consistent with the EAA:NEAA ratio and Lys availability.

[The evaluation of biological value and immunochemical characteristics of the coagulated chicken egg white]

The aim of the study was to investigate in vivo the biological value of the coagulated chicken egg white on growing rats and a comparative immunochemical evaluation in vitro of its antigenic power. The experiment was carried out on 50 growing Wistar male rats with a body weight of 80±5 g. The animals were randomly divided into 3 groups (n=16): control group G1 and two experimental groups G2 and G3. The animals of the control group (G1) received a basic isocaloric and isonitrogenous (20% protein of casein by caloric content) semi-synthetic diet. The animals of the experimental groups G2 and G3 received the same semi-synthetic diet in which casein was replaced by chicken egg white (CEW) and coagulated CEW, respectively. The average food intake of group G3 animals, who received the CEW coagulate, was significantly lower (13.7±0.6 g per day, p<0.05) in comparison with the control group G1 (18.4±0.6 g) and the experimental group G2 (19.2±0.5 g). Moreover, body weight gain of animals treated with coagulated CEW didn't differ significantly from the control G1 animals. Already on the 8th day of the experiment, the body weight gain of G2 animals, who consumed native CEW, was significantly higher in comparison with both other groups. The protein efficiency ratio (PER) for animals of the G3 group was significantly higher (1.96±0.04) than the values for the animals of the control group G1 receiving casein (1.49±0.05, p<0.01), and for the animals of the experimental group G2 receiving CEW (1.60±0.02, p<0.05). The results of immuneenzymatic testing of the initial antigenic power of ovalbumin in native CEW indicated that its content was 33.0% relative to the standard ovalbumin value, antigenic power of which was assumed to be 100%. The developed process of coagulation contributed to a decrease in antigenic power to 2.17%. The obtained data indicate a high biological value and low antigenic power of the coagulated CEW, which makes it prospective for the usage in the composition of food products of mass demand and specialized food products.

Research and regulatory gaps for the substantiation of protein content claims on foods

Protein claims provide guidance to consumers seeking protein-rich foods. Protein claim regulations differ globally, and both Canada and the United States require protein quality assessments. A tripartite workshop identified the need to (i) harmonize, (ii) update existing amino acid composition and digestibility databases, (iii) develop non-animal bioassays, and (iv) evaluate the impact of protein claims on human health. The Protein-Digestibility Corrected Amino Acid Score method is recommended for current regulatory use in Canada.

Effect of germination on chemical, functional and nutritional characteristics of wheat, brown rice and triticale: a comparative study

BACKGROUND

Germination is accompanied by various metabolic reactions in the seed, which lead to alteration of its chemical composition as compared to raw seed. Among the micromolecules, amino acids play an important role in various growth and metabolic activities in seeds.

RESULTS

Results indicated that germination altered seeds' chemical composition, which improved/changed the functional properties investigated such as bulk density, foaming capacity, water holding capacity, oil binding capacity and emulsification properties. Essential amino acids were increased during germination, which contributed in enhancing the nutritional quality of protein in seeds. Germination also improved protein-based quality parameters such as essential amino acid index, biological value, protein efficiency ratio and nutritional index in seeds of brown rice, wheat and triticale. Among the grains, the essential amino acid index of brown rice was reported to be highest after germination.

CONCLUSION

Indispensable/essential amino acids such as lysine, methionine, leucine, isoleucine, threonine, phenylalanine and valine showed a significant increase during germination. As a result, amino acid scoring based on the reference pattern of an FAO Expert Consultation Report (2013) for infants and adults was appreciably improved after germination along with an increase in the essential amino acid indices for brown rice (78.78), wheat (76.55) and triticale (73.99). © 2017 Society of Chemical Industry.

An Appetite for Modernizing the Regulatory Framework for Protein Content Claims in Canada

The need for protein-rich plant-based foods continues as dietary guidelines emphasize their contribution to healthy dietary patterns that prevent chronic disease and promote environmental sustainability. However, the Canadian Food and Drug Regulations provide a regulatory framework that can prevent Canadian consumers from identifying protein-rich plant-based foods. In Canada, protein nutrient content claims are based on the protein efficiency ratio (PER) and protein rating method, which is based on a rat growth bioassay. PERs are not additive, and the protein rating of a food is underpinned by its Reasonable Daily Intake. The restrictive nature of Canada’s requirements for supporting protein claims therefore presents challenges for Canadian consumers to adapt to a rapidly changing food environment. This commentary will present two options for modernizing the regulatory framework for protein content claims in Canada. The first and preferred option advocates that protein quality not be considered in the determination of the eligibility of a food for protein content claims. The second and less preferred option, an interim solution, is a framework for adopting the protein digestibility corrected amino acid score as the official method for supporting protein content and quality claims and harmonizes Canada’s regulatory framework with that of the USA.

Determination of the protein quality of cooked Canadian pulses

A study to determine the protein digestibility-corrected amino acid score and protein efficiency ratio of nine different cooked Canadian pulse classes was conducted in support of the establishment of protein quality claims in Canada and the United States. Split green and yellow pea, whole green lentil, split red lentil, Kabuli chickpea, navy bean, pinto bean, light red kidney bean, and black bean were investigated. Protein digestibility-corrected amino acid score (PDCAAS) and the protein efficiency ratio (PER) were determined using the appropriate rodent models. All pulses had high digestibility values, >70%, with PDCAAS values greater than 0.5, thereby qualifying as a quality protein in the United States, but only navy beans qualified as a good source of protein. All pulses except whole green lentils, split red lentils, and split green peas would qualify as sources of protein with protein ratings between 20 and 30.4 in Canada. These findings support the use of pulses as protein sources in the regulatory context of both the United States and Canada.

Impact of Processing on the Protein Quality of Pinto Bean (Phaseolus vulgaris) and Buckwheat (Fagopyrum esculentum Moench) Flours and Blends, As Determined by in Vitro and in Vivo Methodologies

Blending of protein sources can increase protein quality by compensating for limiting amino acids present in individual sources, whereas processing grain flours by extrusion or baking can also alter protein quality. To determine the effect of baking and extrusion on the protein quality of blended flours from buckwheat and pinto beans, a rodent bioassay was performed and compared to an in vitro method of protein quality determination. Overall, extruded products had higher protein efficiency ratio values, increased digestibility, and greater protein digestibility corrected amino acid score (PDCAAS) values than baked products, with the extruded buckwheat/pinto blend having the greatest PDCAAS value of the experimental diets investigated. A correlation was found between both digestibility and PDCAAS values generated from in vitro and in vivo methods. The use of in vitro digestibility analysis should be investigated as a potential replacement for the current rodent assay for nutrient content claim purposes.

In vivo protein quality of selected cereal-based staple foods enriched with soybean proteins

Background

One way to diminish protein malnutrition in children is by enriching cereal-based flours for the manufacturing of maize tortillas, wheat flour tortillas, and yeast-leavened breads, which are widely consumed among low socio-economic groups.

Objective

The aim was to determine and compare the essential amino acid (EAA) scores, protein digestibility corrected amino acid scores (PDCAAS), and in vivo protein quality (protein digestibility, protein efficiency ratio (PER), biological values (BV), and net protein utilization (NPU) values) of regular versus soybean-fortified maize tortillas, yeast-leavened bread, and wheat flour tortillas.

Design

To comparatively assess differences in protein quality among maize tortillas, wheat flour tortillas, and yeast-leavened breads, EAA compositions and in vivo studies with weanling rats were performed. The experimental diets based on regular or soybean-fortified food products were compared with a casein-based diet. Food intake, weight gains, PER, dry matter and protein digestibility, BV, NPU, and PDCAAS were assessed. The soybean-fortified tortillas contained 6% of defatted soybean flour, whereas the yeast-leavened bread flour contained 4.5% of soybean concentrate.

Results

The soybean-fortified tortillas and bread contained higher amounts of lysine and tryptophan, which improved their EAA scores and PDCAAS. Rats fed diets based on soybean-fortified maize or wheat tortillas gained considerably more weight and had better BV and NPU values compared with counterparts fed with respective regular products. As a result, fortified maize tortillas and wheat flour tortillas improved PER from 0.73 to 1.64 and 0.69 to 1.77, respectively. The PER improvement was not as evident in rats fed the enriched yeast-leavened bread because the formulation contained sugar that decreased lysine availability possibly to Maillard reactions.

Conclusions

The proposed enrichment of cereal-based foods with soybean proteins greatly improved PDCAAS, animal growth, nitrogen retention, and PER primarily in both maize and wheat flour tortillas. Therefore, these foods can help to diminish protein malnutrition among children who greatly depend on cereals as the main protein dietary source.

Use of fungal proteases and selected sourdough lactic acid bacteria for making wheat bread with an intermediate content of gluten

This study was aimed at combining the highest degradation of gluten during wheat flour fermentation with good structural and sensory features of the related bread. As estimated by R5-ELISA, the degree of degradation of immune reactive gluten was ca. 28%. Two-dimensional electrophoresis and RP-FPLC analyses showed marked variations of the protein fractions compared to the untreated flour. The comparison was also extended to in vitro effect of the peptic/tryptic-digests towards K562 and T84 cells. The flour with the intermediate content of gluten (ICG) was used for bread making, and compared to whole gluten (WG) bread. The chemical, structural and sensory features of the ICG bread approached those of the bread made with WG flour. The protein digestibility of the ICG bread was higher than that from WG flour. Also the nutritional quality, as estimated by different indexes, was the highest for ICG bread.