Immobilization of Aspergillus oryzae α-galactosidase in gelatin and its application in removal of flatulence-inducing sugars in soymilk

Recent Advances and Perspectives on Food-Grade Immobilisation Systems for Enzymes

The use of enzyme immobilisation is becoming increasingly popular in beverage processing, as this method offers significant advantages, such as enhanced enzyme performance and expanded applications, while allowing for easy process termination via simple filtration. This literature review analysed approximately 120 articles, published on the Web of Science between 2000 and 2023, focused on enzyme immobilisation systems for beverage processing applications. The impact of immobilisation on enzymatic activity, including the effects on the chemical and kinetic properties, recyclability, and feasibility in continuous processes, was evaluated. Applications of these systems to beverage production, such as wine, beer, fruit juices, milk, and plant-based beverages, were examined. The immobilisation process effectively enhanced the pH and thermal stability but caused negative impacts on the kinetic properties by reducing the maximum velocity and Michaelis-Menten constant. However, it allowed for multiple reuses and facilitated continuous flow processes. The encapsulation also allowed for easy process control by simplifying the removal of the enzymes from the beverages via simple filtration, negating the need for expensive heat treatments, which could result in product quality losses.

Cross-linked α-galactosidase aggregates: optimization, characterization and application in the hydrolysis of raffinose-type oligosaccharides in soymilk

BACKGROUND

Cross-linked enzyme aggregates (CLEAs) of α-galactosidase, partially purified from maize (Zea mays) flour, were prepared. The impact of various parameters on enzyme activity was examined to optimize the immobilization procedure. Biochemical characterization of the free and immobilized enzyme was carried out. Stability (thermal, pH, storage and operational stability) and reusability tests were performed. The potential use of the free enzyme and the CLEAs in hydrolysis processes of raffinose-type oligosaccharides present in soymilk was investigated.

RESULTS

α-galactosidase CLEAs were prepared with 47% activity recovery under optimum conditions [1:5 (v/v) enzyme solution:saturated ammonium sulfate solution ratio; 7.5 mg protein and 0.1% (v/v) glutaraldehyde, 6 h, 4 °C, 150 rpm]. α-galactosidase CLEAs exhibited increased stability in comparison to the free enzyme. The CLEAs and the free enzyme showed a maximum activity at 40°C and their optimal pH values were5.5 and 6.0, respectively. Kinetic constants (K_M , V_max and k_cat ) were calculated for the free enzyme and the CLEAs in the presence of p-nitrophenyl-α-d-galactopyranoside, stachyose, melibiose and raffinose. The effect of various chemicals and sugars on enzyme activity showed that both enzyme forms were significantly inhibited by HgCl₂ and galactose. The CLEAs hydrolyzed 85% of raffinose and 96% of stachyose.

CONCLUSION

The α-galactosidase CLEAs, with their satisfactory enzymatic characteristics, have much potential for use in the food and feed industry. © 2019 Society of Chemical Industry.

Enzyme-based processing of soybean carbohydrate: Recent developments and future prospects

Soybean is well known for its high-value oil and protein. Carbohydrate is, however, an underutilized major component, representing almost 26-30% (w/w) of the dried bean. The complex soybean carbohydrate is not easily hydrolyzable and can cause indigestibility when included in food and feed. Enzymes can be used to hydrolyze the carbohydrate for improving soybean processing and value of soybean products. Here the enzyme-based processing developed for the following purposes is reviewed: hydrolysis of different carbohydrate-rich by/products from soybean processing, improvement of soybean oil extraction, and increase of nutritional value of soybean-based food and animal feed. Once hydrolyzed into fermentable sugars, soybean carbohydrate can find more value-added applications and further improve the overall economics of soybean processing.