Protein Extract

A. Velásquez, and R. Arias. 2013. Effect of substrate on the in vitro protein digestibility of extracts generated by Saccharomyces cerevisiae. Cien. Inv. Agr. 40(3): 503-511. The in vitro crude protein (CP) digestibility (D ivcp), true protein digestibility (D tp) and degradation rate (kd cp) were measured in different protein extracts of Saccharomyces cerevisiae (Sc) yeast. These extracts were generated through a biotechnological method (solid state fermentation). Wheat straw (TWS), barley straw (TBS), chili stubble (TCS), oats hull (TOH) and starchglucose powder (TSP; control) were used as substrates for fermentation by Sc, and their effect on the aforementioned kinetic parameters in the generated cellular biomass was evaluated. In 12 mL cultivation medium, 2 mL Sc solution inoculum (6.7×10 6 spores mL-1) was added together with 2 g vegetable substrate (dry) and additional nitrogen source, and the mixture was incubated for 7 days at a constant temperature (26ºC at pH 5) under aerobic conditions. The average CP content of the yeast biomass (DM) was of 45%. The D ivcp and D tp were analyzed (two phases: pepsin/trypsin-pancreatin) after the extraction of the yeast biomass, and an effect of the fermented substrate on these values (P≤0.001 and P≤0.01, respectively) was observed. The greatest digestibility (D ivcp) was obtained with TSP (78.9% CP) and the lowest with TCS (67.1% CP). In addition, differences in the kd cp between the treatments were also observed (P≤0.01). The high contents of CP, D ivcp (71.8% on average) and kd cp (16.4% h-1 on average) suggest that Sc yeast biomass has the potential to become an alternative for the production of animal protein supplements.

Objective: The present study aims to evaluate the antioxidant, antimicrobial and cytotoxic properties of the secondary metabolites and proteins extracted from Clinacanthus nutans. Methods: Methanol (ME) and acetone (AC) and also protein (PE) extracts were obtained from Clinacanthus nutans. Antioxidant activity of sample extracts was examined by using 1,1-Diphenyl-2-Picrydyl Hydrazyl (DPPH) assay and antimicrobial activity was examined by using the agar diffusion method against Bacillus subtilis, Bacillus cereus, Streptococcus pyrogenes, Escherichia coli, and Pseudomonas aeroginosa bacterial strain. The cytotoxic potential was determined by brine shrimp lethality assay. Results: Methanol extract (ME) demonstrated to have the highest antioxidant activity with IC50 value of 98.84 μg/ml, followed by acetone extract (AE) with IC50 value of 134.83µg/ml, and protein extract (PE) with IC50 value of 353.49 µg/ml. Among all of the sample extracts, only methanol crude extracts (ME) displayed moderate inhibition against Gram-positive B. cereus (7.33±1.15 mm) and S. pyrogenes (8.67±0.57 mm) at concentration of 100 mg/ml, while both acetone (AE) and protein (PE) extracts had no activity against all tested microorganisms. All extracts from methanol (ME), acetone (AE) and protein (PE) exhibited significant cytotoxic activity against brine shrimps at LC50 7.2 μg/ml, 1.42 μg/ml and 70.6 μg/ml respectively. Conclusion: These data proved that methanol extract from the leaves of Clinacanthus nutans is the most potent among all samples tested and has the potential to be developed as an antioxidant, antimicrobial and cytotoxic agents. Whilst, acetone and protein crude extracts have potent antioxidant and cytotoxicity activities.

Enzymatic hydrolysis is an agro-processing aid that can be utilized in order to improve nutritional quality of protein extracts from many sources. In this study, protein extracts from ungerminated and/or germinated local Egyptian soybean and lupin flours were hydrolyzed using the enzyme papain. The hydrolysis processes were carried out for 2 h and aliquots were withdrawn at different time intervals. We have analysed the protein hydrolysate after 30 min hydrolysis as an example of a partially hydrolyzed protein, and after 120 min as an example of greatly hydrolyzed protein. The hydrolysate (2 h treatment at 80°C and pH 7.4) from both soybean and lupin flour contained significantly decreased trypsin inhibitor activity and urease activity, and a reduced phytate content, which improved the overall protein quality. Hydrolysis caused almost complete inactivation of urease in all soybean and lupin samples regardless if the seeds were germinated or not. High protein content, nitrogen solubility and in vitro protein digestibility was shown after hydrolysis. Total protein content (in g/100 g extract) increased in hydrolyzed samples from 48.1 to 51-60 for soybean (dependent on pre-treatment) and from 36.8 to 39.9-48.6 for lupin. Total essential amino acid content was also increased in papain hydrolyzed samples, compared to that in raw and germinated legumes. More specifically, the amount of lysine, sulphur amino acids, histidine, and to a certain extent isoleucine and threonine increased in samples from both legume species. All soybean samples exhibited antioxidant activity while in lupin samples, only those subjected to hydrolysis showed activity. Generally, it was clearly observed that the longer the duration of enzymatic hydrolysis (within the time frame of the experiment), the higher the improvement of the nutritional quality.

A. Velásquez, and R. Arias. 2013. Effect of substrate on the in vitro protein digestibility of extracts generated by Saccharomyces cerevisiae. Cien. Inv. Agr. 40(3): 503-511. The in vitro crude protein (CP) digestibility (D ivcp), true protein digestibility (D tp) and degradation rate (kd cp) were measured in different protein extracts of Saccharomyces cerevisiae (Sc) yeast. These extracts were generated through a biotechnological method (solid state fermentation). Wheat straw (TWS), barley straw (TBS), chili stubble (TCS), oats hull (TOH) and starchglucose powder (TSP; control) were used as substrates for fermentation by Sc, and their effect on the aforementioned kinetic parameters in the generated cellular biomass was evaluated. In 12 mL cultivation medium, 2 mL Sc solution inoculum (6.7×10 6 spores mL-1) was added together with 2 g vegetable substrate (dry) and additional nitrogen source, and the mixture was incubated for 7 days at a constant temperature (26ºC at pH 5) under aerobic conditions. The average CP content of the yeast biomass (DM) was of 45%. The D ivcp and D tp were analyzed (two phases: pepsin/trypsin-pancreatin) after the extraction of the yeast biomass, and an effect of the fermented substrate on these values (P≤0.001 and P≤0.01, respectively) was observed. The greatest digestibility (D ivcp) was obtained with TSP (78.9% CP) and the lowest with TCS (67.1% CP). In addition, differences in the kd cp between the treatments were also observed (P≤0.01). The high contents of CP, D ivcp (71.8% on average) and kd cp (16.4% h-1 on average) suggest that Sc yeast biomass has the potential to become an alternative for the production of animal protein supplements.

The objective of this work was to evaluate the solid-state fermentation with Rhizopus oryzae CCT 7560 of rice bran for the enrichment of proteins and the antioxidant compounds in the fermented biomass. Fermentation was performed in tray bioreactors at 30ºC for 120 h. Protein extraction was done at alkaline pH, followed by precipitation with acetone. Phenolic compounds were extracted with cold methanol. The maximum protein was recovered from after 120 h (26.6%). The content of total phenolic compounds increased during the fermentation and was maximum after 96 h, which inhibited the DPPH radical by 87%. The promising characteristics of the protein and phenolic extracts of the biomass suggested the application in the coating composition for vegetal tissues preservation.

Pleurotus ostreatus and Lentinula edodes are two of the most commercialized mushrooms species in the world and exhibit the potential to accumulate selenium (Se). The form of Se in the protein extracts of P. ostreatus and L. edodes mushrooms enriched with Se has been investigated with the aim of obtaining a protein extract with high concentrations of selenomethionine (SeMet). For an approach to the speciation of Se incorporated in P. ostreatus proteins, size exclusion high performance liquid chromatography was used in combination with inductively coupled plasma mass spectrometry (SEC-HPLC-ICP-MS) and two-dimensional polyacrylamide gel electrophoresis (2D-PAGE). Se-enriched mushrooms of P. ostreatus and L. edodes were used. The proteins were extracted with phosphate buffer, borate buffer and solubilization buffer (2DE) and were purified by acetone precipitation. The extracts were analyzed by reversed phase high performance liquid chromatography in combination with inductively coupled plasma mass spectrometry (RP-HPLC-ICP-MS). The efficiency of the extraction of Se compounds varied according to the buffer type and the species of fungus. The 2DE buffer was the most efficient, reaching a recovery of 60% and 30% of all Se in the protein extracts of to P. ostreatus and L. edodes, respectively. The main form of Se in the protein extracts was Se-Met. The Se concentration was higher in P. ostreatus than in L. edodes. The P. ostreatus protein extracts with 2DE buffer represent a great potential for obtaining biomass proteins with high SeMet concentrations on an industrial scale. The 2D-PAGE analyses revealed the presence of eight Se-containing proteins. The nutritional value of protein biomass containing SeMet presently has a high potential to be explored by pharmaceutical industries.

Comparative UV absorption spectra analysis was carried out on seeds and seedlings of six Vigna unguiculata (L) Walp
accessions. Optical density (OD) UV absorbance (A) value was taken from A200 to A960 wavelengths using
spectrophotometer. At 280 nm protein content in Vigna unguiculata (L) Walp was between 4.2-5.7 % in seedling and 6.6-
16.9 % in seed. Absorbance spectra between 200-960 nm UV wavelengths of protein extracts from Vigna unguiculata (L)
Walp seeds and seedlings were not the same in each of the six accessions analyzed. The difference in the seeds and
seedlings protein absorbance spectra could possibly be due to difference in their protein chemical composition and shape.
With this level of detail in the analysis, the multiwavelength UV approach has the potential to provide a sensitive biosensor
for the detection, identification and enumeration of various biomolecules.