scholarly journals Analysis of JECFA's draft guideline on “Evaluation of enzyme preparations used in the manufacture of foods”

2020 ◽  
Vol 17 (2) ◽  
Author(s):  
Author(s):  
Е. M. Serba ◽  
М. B. Overchenko ◽  
L. V. Rimareva ◽  
N. I. Ignatova ◽  
А. E. Orekhova ◽  
...  

In the production of alcohol in the preparation of grain raw materials for fermentation, the main role is given to enzyme preparations of amylolytic action, which are key enzymes that catalyze the hydrolysis of starch. Amylolytic enzyme preparations with a different composition of enzymes and their level of activity, a mechanism of biocatalytic effect on starch, and a range of thermal and pH optimum are widely represented on the Russian market. The development of optimal conditions for the preparation of grain wort, the rational selection and dosage of concentrated enzyme preparations, the properties of which correspond to the parameters of the technological process, will ensure the effective preparation of starch for fermentation, and increase the profitability of alcohol production. The aim of this work was to study the influence of enzyme preparations of amylolytic action and the conditions of their use on the efficiency of the process of alcoholic fermentation and the yield of the final product, ethanol. The effect of various dosages of enzyme preparations of glucoamylase action, with a different ratio of the main enzyme glucoamylase and minor enzyme α-amylase, as well as methods for preparing wheat wort on the process of alcoholic fermentation, was studied. It was found that the enzyme preparation, the source of glucoamylase, in which α-amylase was present in a ratio of 15: 1 (in terms of activity level), turned out to be more effective in fermenting prepared wheat wort: its optimal dosage was 8 units. GLS / g starch. The presence of a sufficient amount of α-amylase in this preparation compensated for the dosage of thermostable α-amylase. The alcohol concentration in the mash was 10.2% vol., The alcohol yield was 67.9 cm3 / 100 g of starch. When glucoamylase with a lower ratio of the main and minor enzyme (75: 1) was used at the saccharification stage, an increase in the wort fermentation depth was observed with an increase in the concentration of glucoamylase to 9-10 units of GLS / g and α-amylase to 0.5 units. AC / g. It was also found that an increase in the duration of enzymatic-hydrolytic preparation of the wort had a positive effect on the fermentation process, the alcohol concentration in the mash increased to 10.2 vol.%. It was shown that the introduction of proteases into the wort helps to reduce the viscosity of grain wort, enriching it with assimilable yeast amino acids, which leads to an increase in the yield of alcohol. It has been confirmed that the synergy of the action of enzymes of amylolytic and proteolytic effects on polymers of grain raw materials allows to increase the efficiency of their conversion to ethanol. The conditions of enzymatic-hydrolytic processing of grain raw materials for fermentation are developed. The use of the digestion stage did not significantly affect the fermentation results of wheat wort.


Author(s):  
D.V. Abramov ◽  
◽  
D.S. Myagkonosov ◽  
I.N. Delitskaya ◽  
V.A. Mordvinova ◽  
...  

2019 ◽  
Vol 3 (1) ◽  
pp. 129-137
Author(s):  
Gbadebo E . Adeleke ◽  
Olaniyi T. Adedosu ◽  
Rachael O. Adeyi ◽  
John O. Fatoki

Background: Many plants have been identified for their insecticidal properties as alternatives to synthetic ones, which are toxic to untargeted organisms and environment. Ricinus communis (Castor) has been re-ported to exhibit insecticidal properties against insect pests. Zonocerus variegatus (Grasshopper) is a notable pest of several crops, and has been linked with great economic losses to farmers. The present study investigates the in-vitro toxicity of R. communis seed kernel extract (RCSKE) on the activities of selected antioxidant and hydrolytic enzymes in nymph and adult Zonocerus variegatus (Grasshopper), using cypermethrin (CYPER-M) and chlorpyrifos (CPF) as standard conventional pesticides. Methods: Seed kernel of Ricinus communis (Castor) was subjected to acidified aqueous extraction to obtain the extract (RCSKE). Crude enzyme preparations were obtained from nymph and adult Z. variegatus grass-hoppers. The in-vitro effects of different concentrations (15, 30, 45, 60, 75, 90 and 105μg/ml) each of RCSKE, CYPER-M and CPF on the activities of superoxide dismutase (SOD), catalase (CAT), acetylcholinesterase (AChE) and carboxylesterase (CES) in crude enzyme preparations were estimated spectrophotometrically. The level of statistical significance was 0.05. Results: The RCSKE significantly reduced the in-vitro SOD activity (p < 0.05) in nymph Z. variegatus at all the concentrations, whereas both CYPER-M and CPF significantly reduced the activity only at certain concentrations. The CAT activity in the nymph was significantly decreased by RCSKE and CPF at all the concentrations, but CYPER-M decreased it only at certain concentrations. In adult Z. variegatus, SOD activity was not significantly affected (p > 0.05), while CAT activity was significantly increased (p < 0.05) by the three agents at all the concentrations. The AChE and CES activities in the nymph were significantly reduced by RCSKE, CYPER-M and CPF at all the concentrations. The RCSKE and CPF significantly increased the CES activity, while CYPER-M caused a significant decrease in the activity in adult Z. variegatus. Conclusion: The seed kernel extract of Ricinus communis is an effective pesticidal agent and hence, it could be a source of biopesticide alternative with greater potential than cypermethrin and chlorpyrifos. In addition, the antioxidant, acetylcholinesterase and carboxylesterase enzymes in the nymphs of Z. variegatus grasshoppers are more susceptible to the effect of the extract than in the adult grasshoppers.


2019 ◽  
pp. 30-41 ◽  
Author(s):  
E.P. Sannikova ◽  
A.V. Malysheva ◽  
F.A. Klebanov ◽  
D.G. Kozlov

The capacity of yeast to produce the highly active variants of PLA2 has been confirmed. The high-active variants were based on the original enzyme from the strain А-2688 of Streptomyces violaceoruber. To reduce the enzyme toxicity and to increase its expression, various approaches were tested including point mutations, construction of artificial N- and/or C-end pro-regions, hybridization with other proteins and engineering or inactivation of glycosylation sites. As a main result, the modified PLA2 enzymes were obtained which have the same secretion level as their low-active predecessors, but specific activity of which was at least tenfold higher. As the main feature, the selected mutants were characterized by a lower affinity for Ca2+ that probably accounts for their low toxicity (and high expression capacity) at the stage of biosynthesis and their ability to activate under special conditions, e.g. during the egg yolk fermentation. The data obtained can provide a basis for the cost reduction of highly active PLA2 enzyme preparations in industries where the application of high calcium concentrations is allowed. recombinant phospholipase А2, Streptomyces violaceoruber, yeasts, secretion, producer strain The work was initiated by the Innovation Center Biriuch - New Technologies, Ltd., and was supported within the framework of the State Assignment no. 595-00004-18 PR.


2017 ◽  
Vol 35 (No. 3) ◽  
pp. 236-245 ◽  
Author(s):  
IVANA ALPEZA ◽  
KARIN KOVAČEVIĆ GANIĆ ◽  
ANDREJA VANZO ◽  
STANKA HERJAVEC

Two commercial enzyme preparations were used in the production of wine from the Croatian autochthonous red grape variety Plavac Mali in order to improve the extraction of polyphenolic components from grapes, chromatic parameters, and sensory quality. During two vintages, the conventional maceration without enzymes was compared with the maceration using products with different characteristics: pectinase with additional cellulase and hemicellulase activity and pectinase with inactive yeast cells. Both products affected polyphenolic extraction and colour parameters: intensity and hue, and ratio between the yellow, red, and blue colour in young wines (2 months after fermentation) and at the moment of bottling (9 months after fermentation). The correlation between anthocyanins and colour intensity was very strong. The expected reduction of quantitative chromatic parameters during aging was confirmed. Significantly better results were observed in wines produced with pectinase, in relation to all analysed physical and chemical parameters. The sensory analysis showed that wines produced with pure pectolytic enzymes were significantly better than those produced without the enzymes. A product of the combination of pectolytic enzymes and inactive yeast cells had a partial influence on the improvement of the phenolic and sensory quality. The overall quality was significantly more expressed in wines produced with pectolytic enzymes, especially in young wines.


2000 ◽  
Vol 6 (3) ◽  
pp. 197-205 ◽  
Author(s):  
T. Jimenez ◽  
M.A. Martinez-Anaya

Water soluble pentosans (WSP) from doughs and breads made with different enzyme preparations are characterized according to extraction yield, sugar composition, xylose/arabinose ratio and molecular weight (MW) distribution. Extraction yield was greater for dough than for bread samples, ranging from 0.94 to 1.64%, but bread extracts had a higher purity. Percent of pentoses in purified WSP was greater in pentosanase supplemented samples (28-55%) than in control and amylase containing samples (23-32%). Major sugars were xylose and arabinose, but glucose and mannose also appeared in the extracts. The xylose/arabinose (Xyl/Ara) ratio was 1.3-1.6 and underwent small changes during processing. Enzyme addition caused an increase in Xyl/Ara ratio, attributable to a debranching of arabinoxylans (AX) with higher degree of Ara substitution by arabinofuranosidase. Addition of pentosanases had a significant effect in increasing WSP with MW over 39 000, whereas those of low MW changed only slightly. MW distribution depended on enzyme source, and whereas some enzymes showed activity during fermentation others increased their activity during baking. No synergistic effects were observed in studied variables due to the combination of amylases with pentosanases. Protein in WSP extracts eluted together with ferulic acid suggesting they were linked, but not associated with a determined carbohydrate fraction.


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