Optimization of liquid fermentation conditions for biotransformation zein by Cordyceps militaris 202 and characterization of physicochemical and functional properties of fermentative hydrolysates

Abstract Cordyceps militaris 202 is a potential fungus for biotransformation zein, due to its various proteases, high tolerance and viability in nature. In this article, single factor experiment and response surface methodology were applied to optimize the liquid fermentation conditions and improve the ability of biotransformation zein. The optimized fermentation conditions were as follows: inoculum concentration of 19%, volume of liquor of 130 mL/500 mL and pH of 4.7. Under this condition, the degree of hydrolysis (DH) was 27.31%. The zein hydrolysates from fungi fermentation maintained a high thermal stability. Compared to the original zein, the zein hydrolysates were found to have high solubility, which most likely results in improved foaming and emulsifying properties. Overall, this research demonstrates that hydrolysis of zein by C. militaris 202 is a potential method for improving the functional properties of zein, and the zein hydrolysates can be used as functional ingredients with an increased antioxidant effect in both food and non-food applications.

Kinetic modeling of the enzymatic hydrolysis of proteins of visceras from red tilapia (Oreochromis sp): effect if substrate and enzyme concentration / Modelado de la cinética de la hidrolisis enzimática de proteínas de vísceras de tilapia roja (Oreochromis sp): efecto de la concentración de enzima y de sustrato

Background: the growth of world aquaculture has generated important environmental impacts as discard residues that are important sources of protein, which has been used to manufacture low-value products, such as animal food, fish flour and fertilizers. Objectives: to evaluate the effect of enzyme and substrate concentration on the degree of hydrolysis (DH) of proteins in the red tilapia (Oreochromis sp.) viscera (RTV). Methods: the commercial alcalase 2.4 L enzyme was used at different concentrations to hydrolyse the proteins in RTV at 53.5°C and a pH of 9.5 in a 1 L magnetically stirred, jacketed, glass batch reactor connected to an automatic titrator. Each experiment was conducted over 6 h in which every consumed volume of base was recorded every 5 min to determine the corresponding DH at each point. Results: the results indicated that increasing the enzyme concentration produced an increase in the DH and in the reaction rate, while increasing the substrate concentration produced a decrease in both parameters. For this reason, a mathematical model was adjusted for the inhibition of substrate from the exponential kinetic equation d(DH)/dt = a* EXP[-b* (DH)] to explain the behavior of the DH as a function of substrate concentration in this hydrolytic process. The parameters a and b were estimated from a nonlinear regression. Based on these results, the reaction constants were determined as Ks = 456.75 g L-1, K2 = 1.2191 min-1, Kd = 0.2224 min-1, KM = 1.8963 and K3 = 0.1173 L g-1 min-1, which allowed the generation of a good correlation between the predicted and experimental values at the different evaluated operating conditions. This correlation was supported by a low average relative error (ARE) of 3.26%. Conclusion: under evaluated experimental conditions, the kinetics of the hydrolysis reaction followed a substrate inhibition mechanism without product inhibition, which was adjusted through a typical exponential Equation that involves two parameters (a and b) associated with the kinetic constants (Ks, K2, and Kd).

Antecedentes: el crecimiento de la acuicultura en el mundo ha provocado importantes impactos ambientales como el descarte de residuos que son importantes fuentes de proteína, los cuales han sido usados para manufacturar productos de bajo valor tales como: alimento para animales, harina de pescado y fertilizantes. Objetivo: evaluar el efecto de la concentración de enzima y de sustrato sobre el grado de hidrolisis (GH) de las proteínas presentes en las vísceras de tilapia roja (Oreochromis sp.) (VTR). Métodos: se empleó la enzima commercial alcalasa 2.4 L a diferentes concentraciones para hidrolizar las proteínas presentes en la VTR a 53°C y a un pH de 9.5 en un reactor de vidrio de 1 L con chaqueta, magnéticamente agitado y conectado a un titulador automático. Cada experimento se llevó cabo por 6 h registrando cada 5 min el volumen de base cosumido para determinar el grado de hidrolisis correspondiente a cada punto. Resultados: los resultados indicaron que un incremento en la concentración de enzima producía un incremento en el GH y en la velocidad de reacción, mientras que un aumento en la concentración de sustrato provocaba una disminución en ambos parámetros. Por esta razón, se ajustó un modelo matemático para la inhibición de sustrato a partir de la ecuación de cinética exponencial d(GH)/dt = a*EXP[-b*(GH)] para explicar el comportamiento del GH como una función de la concentración de sustrato en este proceso hidrolítico. Los parámetros a y b fueron evaluados mediante una regresión no lineal. Con base en estos resultados, las constantes de reacción fueron determinadas como Ks = 456.75 g L-1, K2 = 1.2191 min-1, Kd = 0.2224 min-1, KM = 1.8963 and K3 = 0.1173 L g-1 min-1, los cuales permitieron obtener una buena correlación entre los valores experimentales y los predichos a las diferentes condiciones de operación. Esta correlación fue soportada por un bajo error medio relativo del 3.26%. Conclusión: bajo las condiciones experimentales evaluadas, la cinética de la reacción de hidrólisis siguió un mecanismo de inhibición por sustrato sin inhibición por producto, el cual fue ajustado mediante una ecuación típica exponencial que involucra dos parámetros (a and b) asociados a las constantes cinéticas Ks, K2, and Kd.

Enzymatic hydrolysis (pepsin) assisted by ultrasound in the functional Properties of hydrolyzates from different collagens / Hidrólise enzimática (pepsina) assistida por ultrassom nas propriedades Funcionais de hidrolisados de diferentes colágenos

ABSTRACT: Enzymatic hydrolysis (pepsin) assisted with or without ultrasound in the functional properties of hydrolyzates from different collagens were analyzed. Degree of hydrolysis, antioxidant activity (DPPH) and antimicrobial activity (MIC) were assessed. The treatment that resulted in greater antioxidant activity for the fiber sample was with the use of 4% of enzyme and concomitant ultrasound (40.7%), leading to a degree of hydrolysis of 21.7%. For the powdered fiber sample the hydrolysis treatment with use of 4% of enzyme resulted in lower protein content (6.97mg/mL), higher degree of hydrolysis (19.9%) and greater antioxidant activity (38.6%). The hydrolyzates showed inhibitory capacity against gram-negative bacteria Salmonella choleraesuis and gram-positive bacteria Staphylococcus aureus. It can be concluded that enzymatic hydrolysis concomitant or not with the use of ultrasound increased the functionality of the fiber and powdered fiber samples, for the other samples its use as supplementary treatment was not productive, due to the worse results of antioxidant activity (DPPH) reported. However, it provided greater hydrolysis degree.

RESUMO: Foram avaliados os efeitos da hidrólise enzimática (pepsina) assistida com ou sem ultrassom nas propriedades funcionais de hidrolisados de diferentes colágenos. Foi analisado o grau de hidrólise, a atividade antioxidante (DPPH) e a atividade antimicrobiana (MIC). O tratamento que possibilitou maior atividade antioxidante para a amostra fibra foi com a utilização de 4% de enzima e ultrassom concomitante (40,7%), levando a um grau de hidrólise de 21,7%. Para a amostra fibra pó o tratamento de hidrólise com uso de 4% de enzima resultou em menor teor de proteína (6,97mg/mL), maior grau de hidrólise (19,9%) e maior atividade antioxidante (38,6%). Os hidrolisados mostraram capacidade inibitória contra a bactéria gram-negativa Salmonella choleraesuis e gram-positiva Staphylococcus aureus. Pode-se concluir que a hidrólise enzimática concomitante, ou não, ao uso do ultrassom apresentou aumento da funcionalidade das amostras fibra e fibra pó. Para as demais amostras, sua utilização como tratamento complementar, a hidrólise não foi interessante, devido aos piores resultados de atividade antioxidante (DPPH) encontrados. Porém, proporcionou maior grau de hidrólise.

Action of a pancreatin and an Aspergillus oryzae protease on whey proteins: correlation among the methods of analysis of the enzymatic hydrolysates

The objectives of this study were to hydrolyze whey proteins using a pancreatin and an Aspergillus oryzae protease; to evaluate the degree of hydrolysis (DH) and the peptide profile; and to establish the correlations among the analytical methods. Ten hydrolysates were prepared at different reaction times and the highest DH was obtained by the protein content method. Good correlations (r > 0.87) between the methods of formaldehyde and orthophthalaldehyde (OPA), formaldehyde and osmometry as well as osmometry and OPA were observed using pancreatin. Similar results were obtained between OPA and soluble protein content for the A. oryzae protease. The action of pancreatin produced the highest contents of di- and tripeptides (9.07, 7.12 and 6.46%) and the lowest of large peptides (42.43, 41.33 and 41.13%), after 3, 4 and 5 h of hydrolysis, respectively. Using pancreatin, the DH measured by formol titration and OPA was positively correlated with medium peptide content and negatively correlated with large peptide content. For the A. oryzae protease, a strong negative correlation was observed between the large peptide content and the DH measured by the OPA method.

STUDY ON FREE RADICAL SCAVENGING ACTIVITY OF PROTEINASE HYDROLYSATES FROM EGG WHITE / 营养学报

trypsin. The EWPHs with papain for 3h displayed the strongest radical scavenging activity. The values of hydroxyl radical and superoxide free radical scavenging activity were 65.63% and 38.40% respectively. Conclusion EWPHs exhibited free radical scavenging activity and the activity of scavenging hydroxyl radical were stronger than superoxide radical.

Study on enzymic hydrolytic conditions of skin collagen from Oreochromis niloticus / 中国海洋药物

Objective To study the single and combined-enzymic hydrolysis conditions of Oreochromis niloticus skin collagen.Methods Based on the inhibitory activities of six kinds of single enzymic hydrolysates to angiotensin converting enzyme(ACE),bromelain and alcalase(2.4L) were selected as combined-enzyme.The optimal hydrolytic conditions of the skin collagen with the two enzymes were determined by orthogonal test L_(16)(4~(5)).Results and Conclusion The results showed that the optimal hydrolytic conditions of bromelain and alcalase 2.4L were temperature 45℃,pH4.5,E/S 4000U?g~(-1),time 4h,concentration of substrate 6%;and temperature 55℃,pH7.5,E/S 6000U?g~(-1),time 2h,concentration of substrate 4%,respectively.Furthermore,hydrolytic effect would be better when using bromelain in advance,followed by alcalase 2.4L.The hydrolytic degree of the hydrolysates prepared under the provided technology was 30.43%,the ACE inhibitory rate would be as high as(68.65%) in vitro.

Study on the enzymatic hydrolysis technology of oyster / 中国海洋药物

Objective To research the optimum hydrolysis conditions of oyster protein so as to raise the protein recovery and degree of hydrolysis.Methods Considering protein recovery,degree of hydrolysis,bitterness and clarity,the best enzyme was selected;Orthogonal test was designed to determine the best enzyme hydrolysis conditions;Based on hydrolysis and protein recovery,the effect of heat treatment,ultrasound and microwave processing and handling on enzymatic hydrolysis of oyster were investigated.Results and Conclusion Bromelain protease was suitable for the proteolysis of oyster,and the optimal conditions were:pH 6,temperature 55℃,substrate concentration 1∶3,E/S=800U/g,4 hours.In the optimal condition,the recovery of protein and degree of hydrolysis were 67.55%and 29.86% respectively in the hydrolysate.Heating,ultrasound technology and microwave treatments before hydro-lysis were harmful to enzymatic hydrolysis of oyster.