Texturization of a Blend of Pea and Destarched Oat Protein Using High-Moisture Extrusion

Grain protein fractions have great potential as ingredients that contain high amounts of valuable nutritional components. The aim of this study was to study the rheological behavior of destarched oat and pea proteins and their blends in extrusion-like conditions with a closed cavity rheometer. Additionally, the possibility of producing fibrous structures with high-moisture extrusion from a blend of destarched oat and pea protein was investigated. In the temperature sweep measurement (60–160 °C) of the destarched oat protein concentrate and pea protein isolate blend, three denaturation and polymerization sections were observed. In addition, polymerization as a function of time was recorded in the time sweep measurements. The melting temperature of grain proteins was an important factor when producing texturized structures with a high-moisture extrusion. The formation of fibrillar structures was investigated with high-moisture extrusion from the destarched oat and pea protein blend at temperatures ranging from 140 to 170 °C. The protein–protein interactions were significantly influenced in the extruded samples. This was due to a decrease in the amount of extractable protein in selective buffers. In particular, there was a decrease in non-covalent and covalent bonds due to the formation of insoluble protein complexes.

Effects of Harvest and Fertilization Frequency on Protein Yield and Extractability From Flood-Tolerant Perennial Grasses Cultivated on a fen Peatland

Paludiculture, and in particular the cultivation of perennial grasses as biomass feedstock for green biorefineries, may be an economic and environmentally sustainable option for agricultural peatlands in temperate regions. However, the optimal biomass quality for protein extraction from flood-tolerant grasses is largely unknown. The aim of this study was to define the combined effect of harvest and fertilization frequency, with one to five annual cuts, on protein yield and extractability for the grasses tall fescue (TF) and reed canary grass (RCG), cultivated on an agricultural fen peatland in Denmark.The content of protein fractions was determined according to the Cornell Net Carbohydrate and Protein System (CNCPS). We assessed protein extractability by lab-scale biorefinery techniques using a screw-press followed by acid precipitation of true protein. The two methods were compared to correlate potential extractable protein yields with actual biorefinery outputs. We found the highest annual biomass and crude protein (CP) yields in the two cut treatments, with 13.4 and 15.6 t dry matter (DM) ha−1 year−1, containing 2.9–3.4 t CP ha−1 year−1 for TF and RCG, respectively. The highest neutral-extractable (fractions B1 and B2) true protein yields of 1.1 and 1.5 t ha−1 year−1 were found in the two cut treatments, representing 39% (TF) - 45% (RCG) of total CP. Using biorefining techniques, we were able to precipitate up to 2.2 t DM ha−1 year−1 of protein concentrate, containing up to 39% CP. Significant correlations between methods were found, with a distinct relationship between CNCPS fractions B1 + B2 and CP yield of the protein concentrate, indicating the suitability of the CNCPS as an indicator for extractable protein yields. Biomass and CP yields were not significantly improved beyond two annual cuts. However, timing and harvest frequencies significantly affected plant maturity and consequently extractable CP contents and protein concentrate yields. We conclude that TF and RCG are promising feedstocks for green biorefineries due to high biomass, extractable CP, and protein concentrate yields, and highlight the potential of flood-tolerant grasses, cultivated on wet agricultural peatlands, for an enhanced valorisation beyond the common utilisation for bioenergy.

Effect of chitosan coating on the quality characteristics of rohu (Labeo rohita) fillets during chilled storage

The current work was undertaken to examine the effect of chitosan as a natural edible coating on the quality of rohu (Labeo rohita) fillets during 30 days of chilled storage. The fish fillets were treated with different concentrations of chitosan (0.1, 0.25, 0.5 and 1% chitosan) and fish fillet without addition of chitosan was kept as control. Sampling was done initially on the 0th day and thereafter at ten day intervals and were examined periodically for water holding capacity (WHC), water extractable protein (WEP), salt extractable protein (SEP), thiobarbituric acid reactive substances (TBARS), pH, total viable count (TVC), psychrotrophic count (PTC) and sensory characteristics. Findings indicated that chitosan coating aided in retaining the quality and extended the shelf life of rohu fillets during refrigerated storage suggesting the suitability of using chitosan as a bio-preservative to extend the shelf life of chilled stored fish.

Protein yield and extractability of flood-tolerant perennial grasses cultivated on a riparian fen, affected by harvest and fertilisation frequency

<p>Paludiculture, defined as agriculture on wet or rewetted peatlands has been proposed as a mitigation strategy to reverse unsustainable environmental impacts such as land subsidence, nutrient release to surface water and greenhouse gas emissions from traditional agriculture on drained peatland. In particular, the production of biomass feedstock from flood-tolerant perennial grasses for green biorefining to protein and other value-added products may be a viable economic and environmentally sustainable option for temperate peatlands. However, optimal quality characteristics of the biomass for protein extraction have yet to be defined.</p><p>In 2018, field plots cultivated with different flood-tolerant perennial grasses were established in an agricultural fen peatland in Denmark. Of these, a total of eight plots cultivated with reed canary grass (RCG) and tall fescue were each subdivided into six sub-plots with different management regarding harvest and fertilisation. Harvest frequencies ranged from one to five times in the period between mid-May to mid-October at intervals of 4-6 weeks. The sub-plots received fertilisation of 100 kg ha<sup>-1</sup> of both N and K prior to each harvest. Protein extractability of the grasses was assessed by lab-scale biorefinery techniques using a screw press followed by precipitation of true protein in the resulting juice. This was compared with protein fractions classified by the Cornell Net Carbohydrate and Protein System (CNCPS).  The biorefinery extractable protein yields (fresh weight) ranged from 10 % to 25 % of the fresh mass input, dependent on treatment, with summer harvests having the lowest yield. Evaluation of the easily extractable crude protein (CP) CNCPS fractions B1 and B2 showed yields of between 61.8 – 110.7 g CP kg<sup>-1</sup> DM.  Preliminary processing of data showed that the cumulative yields of extractable crude protein for the growing season seem highly affected by management.</p>

THE EFFECT OF MILLING METHOD ON PROTEIN PROFILE IN SORGHUM (Sorghum bicolor L.) KD-4 VARIETY

Milling is of important process to improve nutritional and palatability of sorghum seeds for human consumption. This study investigated the effect of milling process on protein fraction of sorghum flour and the bran. The result showed that dry milled sorghum flour contained higher protein than those of wet milled sorghum flour, and the highest protein content was found on sorghum bran. Dry-milled sorghum flour has protein fraction in albumin, globulin, kafirin and glutelin higher than those of wet-milled sorghum flour. Wet-millled sorghum flour contained high protein fraction in cross link kafirin and cross link glutelin. Different of protein fractions noticed among the samples suggested that the samples contained different in amount of extractable protein and this was due to the differences in total protein.

Speciation of Selenium in Brown Rice Fertilized with Selenite and Effects of Selenium Fertilization on Rice Proteins

Foliar Selenium (Se) fertilizer has been widely used to accumulate Se in rice to a level that meets the adequate intake level. The Se content in brown rice (Oryza sativa L.) was increased in a dose-dependent manner by the foliar application of sodium selenite as a fertilizer at concentrations of 25, 50, 75, and 100 g Se/ha. Selenite was mainly transformed to organic Se, that is, selenomethionine in rice. Beyond the metabolic capacity of Se in rice, inorganic Se also appeared. In addition, four extractable protein fractions in brown rice were analyzed for Se concentration. The Se concentrations in the glutelin and albumin fractions saturated with increasing Se concentration in the fertilizer compared with those in the globulin and prolamin fractions. The structural analyses by fluorescence spectroscopy, Fourier transform infrared spectrometry, and differential scanning calorimetry suggest that the secondary structure and thermostability of glutelin were altered by the Se treatments. These alterations could be due to the replacements of cysteine and methionine to selenocysteine and selenomethionine, respectively. These findings indicate that foliar fertilization of Se was effective in not only transforming inorganic Se to low-molecular-weight selenometabolites such as selenoamino acids, but also incorporating Se into general rice proteins, such as albumin, globulin glutelin, and prolamin, as selenocysteine and selenomethionine in place of cysteine and methionine, respectively.