Preparation and antibacterial activity of a novel maltotetraose product

Resin screening and process optimization for erythritol mother liquor chromatographic separation

In order to improve the utilization value of the erythritol mother liquor, the separation and purification of the erythritol mother liquor was selected in this study. The selected chromatographic separation programme for erythritol crystallizing mother liquor is as follows: Firstly, erythritol is resolved from mannitol and arabitol with DTF-01Ca (Suqing Group) resin and then mannitol is resolved from arabitol with 99Ca/320 (Dowex) resin. At the same time, the chromatographic conditions of the DTF-01Ca (Suqing Group) and 99Ca/320 (Dowex) resins were optimized, resulting in an optimal separation temperature and mobile phase flow rate of 70 °C, 10 ml/min. On this basis, a single-column chromatographic model was used to calculate the TD model parameter (N ) and the mass transfer coefficient (k m   ) of the separation of erythritol mother liquor by DTF-01Ca (Suqing Group) and 99Ca/320 (Dowex) resins. The adsorption isotherms, TD model parameter (N ) and the mass transfer coefficient (k m   ) provides data references for the design and operation of the simulated moving beds (SMB) separation system for the industrial-scale separation of erythritol crystallizing mother liquor.

High-Level Expression and Biochemical Characterization of a Maltotetraose Amylase in Pichia pastoris X-33 for Maltotetraose Production

Maltotetraose amylase, which catalyzes the hydrolysis of amylaceous polysaccharides into maltooligosaccharides with maltotetraose as the main product, is extensively used in the food industry. However, the lack of efficient expression system for maltotetraose amylase has hampered its production and application. In this study, high-level production of a maltotetraose amylase mutant (referred to as Pp-Mta∆CBM) from Pseudomonas saccharophila was achieved in Pichia pastoris X-33. First, the gene of maltotetraose amylase with the carbohydrate-binding module (CBM) removed was codon-optimized and cloned into the pPICZαA vector, followed by transformation into P. pastoris X-33 for expression. Using the promoter PAOX1 and signal peptide α-factor, high-level production of Pp-Mta∆CBM with minimal extracellular impurity proteins was achieved, resulting in an extracellular activity of 367.9 U/mL after 7 days of cultivation in shake flasks. Next, the expressed Pp-Mta∆CBM was purified and characterized. This recombinant enzyme was glycosylated and has maximum activity at 55 ℃ and pH 7.0. Its Km for soluble starch was 4.1 g/L, and its kcat was 3237.6 s-1. Finally, the Pp-Mta∆CBM was found to produce a maximum maltotetraose yield of 57.1% in the presence of 200 g/L of substrate. The findings presented in this study demonstrate the efficient production of Pp-Mta∆CBM in P. pastoris, providing a new expression system for maltotetraose amylase and laying the foundation for its scale-up production and industrial application.

Maltooligosaccharides: Properties, Production and Applications

Maltooligosaccharides (MOS) are homooligosaccharides that consist of 3-10 glucose molecules linked by α-1,4 glycosidic bonds. As they have physiological functions, they are commonly used as ingredients in nutritional products and functional foods. Many researchers have investigated the potential applications of MOS and their derivatives in the pharmaceutical industry. In this review, we summarized the properties and methods of fabricating MOS and their derivatives, including sulfated and non-sulfated alkylMOS. For preparing MOS, different enzymatic strategies have been proposed by various researchers, using α-amylases, maltooligosaccharide-forming amylases, or glycosyltransferases as effective biocatalysts. Many researchers have focused on using immobilized biocatalysts and downstream processes for MOS production. This review also provides an overview of the current challenges and future trends of MOS production.

Malto-oligosaccharides as critical functional ingredient: a review of their properties, preparation, and versatile applications

Malto-oligosaccharides (MOS) are α-1,4 glycosidic linked linear oligosaccharides of glucose, which have a diverse range of functional applications in the food, pharmaceutical, and other industries. They can be used to modify the physicochemical properties of foods thereby improving their quality attributes, or they can be included as prebiotics to improve their nutritional attributes. The degree of polymerization of MOS can be controlled by using specific enzymes, which means their functionality can be tuned for specific applications. In this article, we review the chemical structure, physicochemical properties, preparation, and functional applications of MOS in the food, health care, and other industries. Besides, we offer an overview for this saccharide from the perspective of prospect functional ingredient, which we feel lacks in the current literature. MOS could be expected to provide a novel promising substitute for functional oligosaccharides.

Response surface methodology-optimized extraction of flavonoids with antioxidant and antimicrobial activities from the exocarp of three genera of coconut and characterization by HPLC-IT-TOF-MS/MS

Response surface methodology optimization based on central composite design was applied to extract flavonoids from the exocarp of three coconut genera. The antioxidant and antimicrobial activities and structures of the flavonoids were determined. The results indicated that the optimal extraction conditions were ethanol concentration, 60%; temperature, 50 ℃; time, 90 min; liquid/material ratio, 40 mL/g; ultrasonic power, 150 W. Under these conditions, the yields of green, red and yellow coconut exocarp were 366.03 ± 7.57, 596.38 ± 10.32, and 403.78 ± 5.56 mg rutin/g powder, respectively. The flavonoids exhibited eminent DPPH and ABTS radical scavenging activities with IC₅₀ values of 0.01-0.02 mg/mL. At a concentration of 2 mg/mL, they exhibited antimicrobial activity against Vibrio parahaemolyticus, Listeria monocytogenes, Escherichia coli, Staphylococcus aureus, Salmonella and Pseudomonas aeruginosa. In total, 17 flavonoids and 5 phenolic acids were characterized by UPLC-IT-TOF-MS/MS; among them, catechin, kaempferol, and quercetin were abundant. Yellow coconut had a distinct flavonoid spectrogram from other genera and contained more methoxy flavonoids.