Κυριακή 3 Νοεμβρίου 2019

Microbial assessment of medicinal herbs (Cnidii Rhizoma and Alismatis Rhizoma), effects of electron beam irradiation and detection characteristics

Abstract

Medicinal herbs comprise of heavy microbial contaminations. This study aimed to assess microbial hazards including foodborne pathogens in 20 commercial medicinal herbs, Cnidii Rhizoma (C1–C10) and Alismatis Rhizoma (T1–T10) as well as to evaluate irradiation effects of E-beam on microbial load and detection chracteristics. Four samples (C5, C10, T1, T8) from both herbs with higher microbial load were selected for evaluating the irradiation effect of E-beam (up to 10 kGy) on microbial load and radiation-induced changes in detection markers by standard methods (Codex, Korean Food Code), such as direct epifluorescent filter technique/aerobic plate count (DEFT/APC), photostimulated luminescence (PSL), thermoluminescence (TL), and electron spin resonance (ESR). DEFT/APC revealed non-evidence of pre-sterilization of all samples. PSL differentiated irradiated samples (1, 5, and 10 kGy) of both herbs from non-irradiated (control: 0 kGy). Both TL and ESR methods validated PSL screening results by detecting radiation-induced markers from E-beam irradiated medicinal herbs.

Anti-inflammatory and in vitro bone formation effects of Garcinia mangostana L. and propolis extracts

Abstract

The purpose of this study was to determine the anti-inflammatory and in vitro bone formation effects of Garcinia mangostana L. (mangosteen) and propolis extracts. Immortalized human gingival fibroblasts (hTERT-hNOF) cells were treated with Porphyromonas gingivalis KCOM 2804 lipopolysaccharide followed by treatment with mangosteen and propolis extract alone or in combination. Expression levels of inflammatory cytokines were evaluated by enzyme-linked immunosorbent assay. Effect of mangosteen and/or propolis extracts on mineralization of MG-63 cells was evaluated by alkaline phosphatase activity and alizarin red S staining. Group mangosteen extract complex 1:34 (1 µg/ml mangosteen extract and 34 µg/ml propolis extract) significantly reduced expression levels of IL-6, IL-8, and PGE2. It had higher than other groups in vitro bone formation effect on MG63 cells. These results suggest that mangosteen and propolis extract complex could be used in the prevention and treatment of periodontal disease.

Extraction of γ-oryzanol from rice bran using diverse edible oils: enhancement in oxidative stability of oils

Abstract

Diverse edible oils including perilla, corn, soybean, canola, sunflower, olive, and grape seed oils were mixed with heat-stabilized rice bran to extract γ-oryzanol from the rice bran. The oxidative stabilities of the oils with or without extraction were compared by analyzing the headspace oxygen content, conjugated dienoic acid (CDA) values, and p-anisidine values (p-AV). Grape seed oil extracted significantly high γ-oryzanol content while canola oil extracted lowest γ-oryzanol content (p < 0.05). All the solvent oils except corn oil possessed enhanced oxidative stability at 100 °C after extracting γ-oryzanol from stabilized rice bran, based on the results of the headspace oxygen depletion and CDA methods. However, all the recovered oils had high p-AV than vegetable oils. Especially, perilla oil had an exceptionally high p-AV, which may be due to its high linolenic acid content.

Modelling and kinetic study of microwave assisted drying of ginger and onion with simultaneous extraction of bioactive compounds

Abstract

Onion and ginger are rich sources of bioactive compounds which are lost during conventional drying process. The present study was designed to optimize the novel Microwave Assisted Drying and Extraction technique (MADE) for simultaneous drying and extraction/recovery of bioactive compounds from model food products. The time required for drying of samples was 11 (onion) and 16 (ginger) minutes with recovery yield of 87% (onion) and 85% (ginger). The drying time was reduced to 100 times compared to hot air drying and moisture ratio of dried samples was best described by Midilli model. The diffusivities of onion and ginger slices were 1.27 e−11 and 1.43 e−11 m2/s, respectively. Moreover, microwave-based extraction was compared with conventional one. The results of antioxidant activity and total phenolic contents of condensates obtained through MADE were higher compared to conventional method. In short, MADE exhibited better yield of extraction and drying properties compared to conventional methods.

Emulsion stabilization mechanism of combination of esterified maltodextrin and Tween 80 in oil-in-water emulsions

Abstract

Esterified maltodextrins (EMs) were prepared using enzyme-catalyzed reaction of maltodextrin (DE of 16 and 9) and palmitic acid. The emulsion stabilization mechanism was investigated of a combination of Tween 80 and EM in oil-in-water emulsion to determine interfacial tension, ζ-potential, non-adsorbed Tween 80 in centrifuged-serum of emulsion, and fluoresced microstructure. The interfacial tension and non-adsorbed Tween 80 content of combination of Tween 80 and EM-stabilized oil-in-water emulsions were closed to those of sole Tween 80-stabilized emulsion. The ζ-potential of sole Tween 80-stabilzed emulsion had a small positive charge but ζ-potential changed to small negative charge as EM was added into Tween 80-stabilzed emulsion. Fluorescence microstructure confirmed that EM was adsorbed on oil droplet surface, stabilized by Tween 80. The mechanism of emulsion stabilization may conclude that Tween 80 was mainly adsorbed at oil surface and EM may interact with Tween 80 to form a double stabilization layer without competitive replacement.

Versatile biotechnological applications of amylosucrase, a novel glucosyltransferase

Abstract

Amylosucrase (AS; EC 2.4.1.4) is an enzyme that has great potential in the biotechnology and food industries, due to its multifunctional enzyme activities. It can synthesize α-1,4-glucans, like amylose, from sucrose as a sole substrate, but importantly, it can also utilize various other molecules as acceptors. In addition, AS produces sucrose isomers such as turanose and trehalulose. It also efficiently synthesizes modified starch with increased ratios of slow digestive starch and resistant starch, and glucosylated functional compounds with increased water solubility and stability. Furthermore, AS produces turnaose more efficiently than other carbohydrate-active enzymes. Amylose synthesized by AS forms microparticles and these can be utilized as biocompatible materials with various bio-applications, including drug delivery, chromatography, and bioanalytical sciences. This review not only compares the gene and enzyme characteristics of microbial AS, studied to date, but also focuses on the applications of AS in the biotechnology and food industries.

Effect of ripening time on bacteriological and physicochemical goat milk cheese characteristics

Abstract

Cheese ripening involves lactose metabolism, lipolysis and proteolysis, which are affected by many factors. The aim of this study was to assess changes due to ripening (90 days) of goat milk cheese through bacteriological and physicochemical analysis in order to verify if, at the end of ripening period, this cheese could be considered “lactose-free”. Three batches of the goat milk cheese were manufactured and ripened at 10 °C and 80% relative humidity for 90 days. Titratable acidity increased by about 59 °D due to carbohydrate degradation and organic acid production. However, pH (5.31–5.25) remained constant. Lactococcus was the dominant cheese microbiota, acting in the fermentation of lactose (1.17–0.06 mg/g) and lactic acid production (5.49–s10.01 mg/g). Thus, ripening time was decisive for bacteriological and physicochemical goat milk cheese characteristics.

Inula britannica fermented with probiotic Weissella cibaria D30 exhibited anti-inflammatory effect and increased viability in RAW 264.7 cells

Abstract

The objective of this study was to increase the bioavailability of Inula britannica (IB) through fermentation with probiotic Weissella cibaria D30, and to evaluate the chemical composition, viability, and anti-inflammatory effect of fermented I. britannica (FIB). IB was fermented with W. cibaria D30 at 37 °C for 24 h. FIB increased total phenolic content and decreased total flavonoid content of IB. 1-O-acetylbritannilactone and ergolide production, which are associated with the viability, increased from 1.38 to 4.13 μg/mg, and decreased from 5.24 to 0.94 μg/mg, in the control and FIB, respectively. In addition, the cell viability of RAW264.7 cells increased when pretreated with 400 μg/mL FIB. FIB inhibited the production of nitric oxide and proinflammatory cytokines by inhibiting NF-κB and MAPKs pathways. Therefore, FIB with W. cibaria D30 reduced the toxicity and increased the anti-inflammatory properties. These results indicate that FIB is a potential beneficial bioactive agent for functional foods.

Effects of different carbohydrases on the physicochemical properties of rice flour, and the quality characteristics of fermented rice cake

Abstract

The rice flours were hydrolyzed using α-amylase (A), α-amylase and xylanase (AX), and α-amylase, xylanase and β-amylase (AXB). The effects of different enzymatic rice flour hydrolysates (ERH) on the quality of the fermented rice cake (FRC) were determined at 25 °C for 4 days. ERH had higher porosity, water absorption index, water solubility index and lower viscosity than the control. Moisture content of FRC center decreased significantly after 4 days. Specific volumes of fresh A-, AX- and AXB-FRC were higher than the control. Color of fresh A-FRC was closer to that of the control. AXB-FRC had lower hardness and firming rate than other samples during storage. After 4 days of storage, FRC with ERH had lower endotherm enthalpy and more uniform and clearer pore structure than the control. Therefore, the ERH with single or mixed enzymes could improve the structure of FRC, and extend its shelf-life.

N ε -(carboxymethyl)lysine formation from the Maillard reaction of casein and different reducing sugars

Abstract

Dietary advanced glycation end products (AGEs) are involved in the pathogenesis of diabetic complications, atherosclerosis, and kidney disease. Formation of Nε-(carboxymethyl)lysine (CML), a well-known AGEs, was evaluated from the reaction of casein from bovine milk with different reducing sugars (glucose, tagatose, and xylose) at various sugar concentrations and heating temperatures (75 and 120 °C) used in food processing to determine the best sweetener to be used in dairy products. The concentration of CML was measured using an enzyme-linked immunosorbent assay. Additionally, SDS-PAGE was carried out to observe the changes in the molecular weight of casein. The results reveal that tagatose leads to a lower CML concentration at 75 °C than glucose or xylose, whereas no significant differences are observed at 120 °C. We conclude that it would be more appropriate to use tagatose rather than glucose or xylose as a sweetener, considering the AGEs contents in heat-treated dairy products.

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