Inhibitory Effects of Phenolics and Saponins From Commonly Consumed Food Legumes in China Against Digestive Enzymes Pancreatic Lipase and α-Glycosidase

Total phenolic and saponin components were extracted from 13 commonly consumed food legumes produced in China, and then a systematic comparative study was conducted to investigate their inhibitory effects against digestive enzymes, pancreatic lipase, and α-glycosidase, respectively. Saponin extract (1 mg/mL) from black bean exhibited the highest (41.8%) pancreatic lipase inhibitory effect, followed by phenolic extract from adzuki bean with 36.3%, saponin extract from yellow soybean with 34.1%, saponin extract from pinto bean with 32.6%. It is worth mentioning that both phenolic and saponin extracts from the mung bean, adzuki bean, lima bean, and pinto bean exhibited inhibitory effects against pancreatic lipase. Among four beans, the adzuki bean had the highest inhibitory effects against pancreatic lipase activity. In the α-glycosidase assays, phenolic extracts exhibited stronger α-glycosidase inhibitory activity than that of saponins in general. Phenolic extracts of the adzuki bean, black bean, fava bean, lentil, rock bean, and red kidney bean inhibited over 80% of α-glycosidase activity at the concentration of 1 mg/mL. Both phenolic and saponin extracts from the adzuki bean and rock bean exhibited inhibitory effects against α-glycosidase. The results indicate that adzuki bean is one of the best target beans for further study on their anti-obesity and anti-diabetes effects via cell and animal models.     

Optimization of Phenolic Content,Antioxidant, and Inhibitory Activities of α-Glucosidase and Angiotensin Converting (AC) Enzymes from Zingiber officinale Z.

The optimum extraction conditions of phenolic compounds from ginger were evaluated with respect to antioxidant activity and angiotensin converting enzyme and α-glucosidase inhibitory activities. Free phenolics were extracted under conditions that varied according to extraction time, temperature, and solvent type (water, acetone, and methanol). Acid and base hydrolysis reactions were used to obtain bound phenolic compounds from ginger. The results showed that the type of solvent used and the temperature and time of extraction needed for maximal total phenolic content, antioxidant activity, and angiotensin converting enzyme inhibitory activity differed greatly from solvent conditions and showed the greatest α-glucosidase inhibitory activity. The predominant free phenolics in the methanol extracts included diosmin, thymol, and carvacrol, which varied greatly according to solvent extraction conditions (i.e., time and temperature). Diosmin was the predominant bound phenolic compound of the methanol extracts. The present study findings indicate that differing solvent extraction protocols involving extraction time and temperature for ginger need to be explored to generate specific optimal bioactivities of the extracts, which are related to the pattern of predominant phenolics in those extracts.     

In Vitro Potential of Ascophyllum nodosum Phenolic Antioxidant-Mediated α-Glucosidase and α-Amylase Inhibition

ABSTRACT: Ascophyllum nodosum is a brown seaweed that grows abundantly in the Northeast coastal region. In this study, the potential of A. nodosum for type 2 diabetes management through antioxidant-mediated α-glucosidase and α-amylase inhibition was investigated. After the initial screening of 4 locally harvested seaweeds, A. nodosum was chosen for its highest phenolic content and was subjected to water extraction. Among extraction ratios of 50 g to 100 to 1000 mL at room temperature, 50 g/400 mL yielded the highest phenolic content of 4.5 mg/g wet weight. For evaluation of extraction temperature ranging from 20 to 80 °C, 50 g/400 mL was chosen as a minimum amount of extractant. Among temperatures studied, extraction at 80 °C resulted in the highest total phenolic contents (4.2 mg/g wet weight). All extracts had similar levels of antioxidant activity in the range of 60% to 70% in terms of 1, 1-diphenyl-2-picrylhydrazyl (DPPH) free radical scavenging activity. The 80 °C extract had the highest α-glucosidase and α-amylase inhibitory activity with IC₅₀ of 0.24 and 1.34 μg phenolics, respectively, compared to the IC₅₀ of acarbose, reference inhibitor, being 0.37 and 0.68 μg. The results show that fresh A. nodosum has strong α-glucosidase and mild α-amylase inhibitory activities that correlated with phenolic contents. This study suggests a nutraceutical potential of A. nodosum based on phytochemical antioxidant and antihyperglycemia activities.     

Effect of Processing on Phenolic Antioxidants of Fruits,Vegetables, and Grains—A Review

Understanding the influence of processing operations such as drying/dehydration, canning, extrusion, high hydrostatic pressure, pulsed electric field, and ohmic heating on the phytochemicals of fruits, vegetables, and grains is important in retaining the health benefiting properties of these antioxidative compounds in processed food products. Most of the previous investigations in the literature on the antioxidants of fruits, vegetables, and grains have shown that food-processing operations reduced the antioxidants of the processed foods, which is also the usual consumer perception. However, in the last decade some articles in the literature reported that the evaluation of nutritional quality of processed fruits and vegetables not only depend on the quantity of vitamin C but should include analyses of other antioxidant phytochemicals and antioxidant activity. Thermal processing increased the total antioxidant activity of tomato and sweet corn. Most importantly, analysis also depends on the condition, type, and mechanism of antioxidant assays used. This review aims to provide concise information on the influence of various thermal and nonthermal food-processing operations on the stability and kinetics of health beneficial phenolic antioxidants of fruits, vegetables, and grains.     

Effect of Different Drying Treatments and Solvent Ratios on Phytochemical Constituents of Ipomoea aquatica and Correlation with α-Glucosidase Inhibitory Activity

Ipomoea aquatica is an aquatic plant that is widely consumed in Southeast Asia as a vegetable. In this study, the influence of various ethanol ratios (0, 20, 50, 80, and 100%) as an extraction solvent and different drying methods including air drying, sun drying, and oven drying on phytochemical constituents of I. aquatica was investigated using a proton nuclear magnetic resonance-based metabolomics approach. The effect on α-glucosidase inhibitory activity and total phenolic content was also examined. Clear discrimination was observed between different ethanol ratios and different drying processes by principal component analysis. The highest α-glucosidase inhibitory activity was observed for absolute ethanol extract from the oven drying method with IC₅₀ value of 204.0 ± 59.0 µg/mL and total phenolic content value of 22.0 ± 0.7 µg gallic acid equivalent/mg extract. Correlation between the α-glucosidase inhibitory activity and the metabolite were analyzed using a partial least square analysis. The metabolites that are responsible for the activity were quercetin derivatives, chlorogenic acid derivatives, sucrose, and fructose. This study highlights the basis for future investigations of I. aquatica as a source of food that has the potential for nutraceutical enhancement and as ingredient in medicinal preparation.     

Effects of α-tocopherol level in raw venison on lipid oxidation and volatiles during storage

Relationships between α-tocopherol concentration in the muscle and development of lipid oxidation or volatiles in raw venison were studied. Fourteen Japanese Shika Deer (Cervus nippon) were fed various amounts (0–3.0 g of α-tocopheryl acetate per animal) during the different periods (0–37 days) and then M. longissimus thoracium et lumborum (LD muscles) with a range of α-tocopherol concentrations (4.1–15.1 mg/kg tissue) were obtained. For stabilizing the lipid during storage for 11 days under air, over ca. 9 mg of α-tocopherol per kg tissue were required based on levels of 2-thiobarbituric acid reacting substances (TBARS) numbers. Nine compounds were identified in headspace volatiles, and one of the volatiles was hexanal which has been recognized as off-flavour component. For depressing the hexanal evolution, at least ca. 9 mg of α-tocopherol per kg tissue were also required for 11 days’ storage. This value was much higher than other species. The reasons for higher requirement of α-tocopherol were possibly due to the higher concentration of unsaturated fatty acid and myoglobin in venison.     

Inhibitory properties of polyphenols in Malus “Winter Red” crabapple fruit on α-glucosidase and α-amylase using improved methods

To explore the inhibitory activity of polyphenols on α-glucosidase and α-amylase, 16 polyphenols were isolated, identified, and quantified in an edible Malus “Winter Red” crabapple fruit. The limitations of two traditional methods for α-glucosidase and α-amylase activity assay in vitro were assayed. An improved method based on an HPLC assay for α-glucosidase and a colorimetric method coupled with a custom-made mini-column for α-amylase were established. Compared with positive controls, acarbose and miglito, most polyphenols, especially the four aglycones (cyanidin, quercetin, phloretin, and 3-hydroxyphloretin) showed higher inhibition rates on α-glucosidase. None of the polyphenols showed higher inhibition rates on α-amylase than acarbose, but most, especially the four aglycones, showed higher inhibition rates on α-amylase than miglito. The Malus Winter Red fruit has great potential for postprandial blood glucose management as a potential diet therapy for diabetic patients.     

Effects of α-lipoic acid supplementation on malondialdehyde contents and superoxide dismutase in rat skeletal muscles

This study investigated the effects of α-lipoic acid (ALA) supplementation on the malondialdehyde (MDA) contents and superoxide dismutase (SOD) protein expression in rat skeletal muscles under non-exercising condition. Fourteen Sprague-Dawley male rats at the age of 6 weeks were randomly divided into 2 groups CS, (normal diet group, n=7) and AS (0.5% ALA supplemented diet group, n=7), and keep non-exercising condition for 4 weeks. The muscle MDA concentration of the AS group was significantly lower than that of the CS group in the both soleus and extensor digitorum longus muscles. The expressions of Cu/Zn-SOD and Mn-SOD proteins in the soleus muscle were significantly higher in the AS group than that in the CS group. From these results, ALA supplementation under non-exercising condition had a role in increasing of antioxidant enzymes in skeletal muscle types of rats.     

Effects of chitosan and collagen containing α-tocopherol on the oxidative stability in bulk oil and oil-in-water emulsion

To provide efficient antioxidant capacities, proper carriers are needed to protect antioxidants against oxidative stress. Collagen mesh structure or chitosan gel was loaded with α-tocopherol and their effects were evaluated in bulk corn oil or oil-in-water (O/W) emulsion at 60 °C. Added collagen and chitosan enhanced oxidative stability in corn oil and O/W emulsions at 60 °C compared to corn oils without carriers or with addition of α-tocopherol (p < 0.05). Stability of α-tocopherol in corn oil loaded in collagen or chitosan was significantly enhanced compared to that in oils without carriers (p < 0.05). In O/W emulsions, α-tocopherol loaded collagen showed higher antioxidant properties than α-tocopherol loaded chitosan (p < 0.05). Collagen mesh structure and chitosan gel retarded the rates of lipid oxidation efficiently in both food matrices when α-tocopherol was not loaded. Collagen mesh structure and chitosan gel can be useful carriers for α-tocopherol in bulk oil or O/W emulsion.     

Phenolic composition,antioxidant capacity and inhibitory effects on α-glucosidase and lipase of immature faba bean seeds

Immature faba bean seeds of five varieties were investigated for changes in phenolic composition, antioxidant capacity and inhibitory effects on α-glucosidase and lipase at three edible stages (S1, S2 and S3). Phenolics and antioxidant capacity in seed coats were significantly higher than those in cotyledons, and the highest was found of FD18 at stage S3. While phenolic content in cotyledons decreased steadily with the harvest time delayed. Eight phenolic compounds were confirmed with epicatechin and catechin prominent and their levels showed a great variability depending on varieties, maturation stages and plant parts of faba bean seeds. Unexpectedly, the inhibitory effects of purified phenolics on α-glucosidase were even stronger than that of the positive control acarbose, and the inhibitory effects on lipase in the cotyledons declined gradually from stage S1 to S3. Significant positive correlations between phenolics from seed coats and antioxidant capacity, and phenolics from cotyledons and the enzyme inhibitory effects were observed. Overall, the immature faba bean seed, especially its seed coat, has great potential as a functional food.     

Effects of rendering and α-tocopherol addition on the oxidative stability of horse fat

Food Science and Biotechnology - Oxidative stability of horse fat rendered at 70&nbsp;°C, − 0.1&nbsp;MPa under vacuum and 110&nbsp;°C, 0.1&nbsp;MPa from horse...     

Inhibitory activities of extracts from Cleistocalyx operculatus flower buds on pancreatic lipase and α-amylase

In this work, we investigated the inhibitory activities of aqueous extract (Eaq), 30, 60, and 95?% ethanol extracts (E₃et, E₆et, and E₉et), petroleum ether extract (Epe), ethyl acetate extract (Eae), and 2′,4′-dihydroxy-6′-methoxy-3′,5′-dimethylchalcone (DMC) from Cleistocalyx operculatus flower buds on pancreatic lipase and α-amylase, which were closely related to body weight and obesity. The inhibition effect of various extracts was determined by the Lineweaver–Burk plots. The results showed that the IC₅₀ values of DMC, Epe, Eae, and E₉et against pancreatic lipase were 101.5?μM, 38.65, 76.62, and 109.76?μg/ml, respectively, which were much lower than that of E₃et and E₆et. Eaq, E₃et, E₆et, and DMC strongly inhibiting the pancreatic α-amylase, with IC₅₀ values of 73.10, 165.93, 231.23?μg/ml, and 69.35?μM, respectively. Furthermore, the kinetic analysis suggested that the inhibition mode of crude extract against pancreatic lipase was noncompetitive, while that against pancreatic α-amylase was competitive. The content of DMC and total polyphenols in each extract were determined by HPLC and spectrophotometric method, respectively. It was interestingly found that the DMC content had profound influence on pancreatic lipase activity, and the total polyphenols content significantly affected the pancreatic α-amylase activity. The findings in this work suggested that extracts from C. operculatus flower buds possess potent inhibitory activity against pancreatic lipase and α-amylase, and provided some new ideas for the prevention and treatment for obesity.     

Effects of hyper-oxygenation and storage of Macabeo and Airén white wines on their phenolic and volatile composition

The effects of hyper-oxygenation and storage period of Macabeo and Airén white wines on color characteristics, phenolic, and volatile composition have been evaluated. Hyper-oxygenation treatment provoked a significant decrease in virtually all individual phenolic compounds in must, young wine, and one-year-aged wines, above all hydroxycinnamic acid derivatives, flavonols, and the new GRP derivatives compounds (derived from 2-S-glutathionyl-caftaric acid or grape reaction product). Despite this fact, the contribution of the yellow color component (b*) of white wines derived from hyper-oxygenated musts was significantly higher in comparison with untreated ones, even after 1 year of bottle storage. On the other hand, the concentration of major volatile compounds and some alcohols (namely, C₆ alcohols, terpenes, and lactones) was higher in wines derived from hyper-oxygenated musts, but the hyper-oxygenation effect on volatile profile deeply depended on the grape variety. After 1 year of bottle storage, the significant differences were maintained and the content of some long-chain esters increased as a consequence of oxygen addition.     

In Vitro Hypoglycemic Activity of the Phenolic Compounds in Longan Fruit (Dimocarpus longan var. Fen Ke) Shell Against α-Glucosidase and β-Galactosidase

The in vitro hypoglycemic effect of longan fruit (Dimocarpus longan var. Fen Ke) shell extracts was evaluated by inhibiting α-glucosidase and β-galactosidase activities. The IC₅₀ values of hot water and 50% ethanol ultrasonic extracts against the α-glucosidase were 9.2 and 13.4 mg/mL, and those against the β-galactosidase were 12.9 and 19.7 mg/mL, respectively. The hot water extracts (20 mg/mL) with aid of ultrasound-assisted extraction may enhance the inhibitory rates of α-glucosidase and β-galactosidase by 10.6 and 12.0% as compared with conventional extraction, respectively. Two phenolic compounds, gallic acid and ellagic acid, were identified as the major phenolic in hot water extracts from longan fruit shell against α-glucosidase and β-galactosidase. Inhibition of α-glucosidase and β-galactosidase were proven to be as a therapeutic approach for decreasing postprandial hyperglycemia. As a result, the longan fruit shell extracts may develop to be as a potential strategy for early treatment of postprandial hyperglycemia.     

Species of Cronobacter – A review of recent advances in the genus and their significance in infant formula milk

Enterobacter sakazakii has recently been reclassified as the novel genus Cronobacter. These bacteria have been associated with disease outbreaks and sporadic infections, particularly in premature and immunocompromised infants. Cronobacter spp. can cause foodborne infections such as neonatal meningitis, septicaemia and necrotising enterocolitis. Infant formula milk is the only food source that has been epidemiologically linked to disease outbreaks caused by Cronobacter spp. This holds particular risk for premature and immunocompromised infants. This review focuses on the recent reclassification of Cronobacter and the importance that these pathogens pose to the food industry. The inactivation, inhibition, thermal, osmotic and desiccation tolerances of these bacteria are described, as well as improvements made in the isolation and detection methods of members of Cronobacter from food products.     

Effects of Monascus-fermented grain extracts on plasma antioxidant status and tissue levels of ubiquinones and α-tocopherol in hyperlipidemic rats

We investigated the effects of Monascus-fermented mixed grain extracts (MFGEs) enriched with bioactive mevinolins (natural statins) and coenzyme Qs (CoQ₉ + CoQ₁₀) on the blood lipids, antioxidant status, and tissue levels of CoQs and α-tocopherol (α-Toc) in hyperlipidemic rats. The oral administration of MFGEs (300 mg/kg body weight per day) for 8 weeks resulted in a significant decrease in blood levels of total cholesterol (TC), triglycerides (TG), low-density lipoprotein cholesterol (LDL-C), and LDL-C/high-density lipoprotein cholesterol (HDL-C) ratio compared to the control and lovastatin supplement group of a dosage of 20 mg/kg per day (p < 0.05). Furthermore, a significant increase in the ratios of α-Toc/LDL-C and CoQs/LDL-C in plasma and tissues and improvement in plasma antioxidant status as measured by TBARS and TRAP were observed in hypercholesterolemic rats (p < 0.05). Regarding the effects of MFGEs on antioxidant levels of plasma and tissues, there were significant increases in the levels of α-Toc (p < 0.05) and CoQs (p < 0.01) after the 8-week MFGEs treatment. These data indicate that MFGEs supplementation not only decreases blood lipids and lipid peroxidation but also increases levels of antioxidants such as α-Toc and CoQs and may improve plasma antioxidant status as well as a hypolipidemic effect.     

Effects of Processing and NaCl on Angiotensin I-Converting Enzyme Inhibitory Activity and γ-Aminobutyric Acid Content During Sufu Manufacturing

In the present study, sufu, the cheese-like, traditional fermented soybean food from China, was prepared by solid-state fungal fermentation and ripened in dressing mixtures with different NaCl content. The angiotensin I-converting enzyme (ACE) inhibitory activity and γ-aminobutyric acid (GABA) content were determined during sufu manufacturing. The influence of NaCl on ACE inhibitory activity and GABA content was also investigated. The ACE inhibitory activity and GABA content of sufu were significantly affected by processing and NaCl content. During fermentation, the ACE inhibitory activity percentage increased from 11.55 to 37.61 %, whereas the GABA content increased from 32.64 to 133.13 mg/100 g dry matter. The salting process caused a decrease in both. Generally, the ACE inhibitory activity and GABA content increased during ripening. The ACE inhibitory activity at the same ripening interval was inhibited by NaCl. After ripening for 8 weeks, the sufu samples with 5 % NaCl had the highest ACE inhibitory activity, with an IC₅₀ of 0.79 mg/mL, whereas the samples with 8 % NaCl had the highest GABA content at 193.5 mg/100 g dry matter. A significant correlation was found between ACE inhibitory activity and peptide content. These results indicated that sufu could be useful in alleviating hypertension because it contained ACE inhibitors and GABA as antihypertensive substances. Low NaCl content could increase the antihypertensive activity.     

Effects of Maillard reaction conditions on the antigenicity of α-lactalbumin and β-lactoglobulin in whey protein conjugated with maltose

The effects of Maillard reaction conditions (weight ratio of protein to sugar, temperature and time) on the antigenicity of α-lactalbumin (α-LA) and β-lactoglobulin (β-LG) in conjugates of whey protein isolate (WPI) with maltose were investigated. Response surface methodology was used to establish models to predict the antigenicity of α-LA and β-LG and find an optimal reaction condition under which the antigenicity of α-LA and β-LG reduces to minimum value. Conjugating WPI with maltose was an effective way to reduce the antigenicity of α-LA and β-LG. The antigenicity of α-LA decreased from 32.25 μg mL⁻¹ to 10.91 μg mL⁻¹. And the antigenicity of β-LG decreased from 272.4 μg mL⁻¹ to 38.17 μg mL⁻¹. Temperature had the greatest effect on the antigenicity of α-LA, while weight ratio of WPI to maltose was the most significant factor on the antigenicity of β-LG.     

Effects of α-tocopherol on the oxidative stability and incorporation of deuterium in volatiles from a linoleic acid-deuterium model system

The effects of α-tocopherol on the oxidative stability and incorporation of deuterium in volatiles were evaluated in linoleic acid-water model systems treated at 60°C by analyzing headspace oxygen depletion, formation of lipid hydroperoxides, and profiles of headspace volatiles. Deuterium oxide accelerated the rates of linoleic acid oxidation compared to samples in deuterium-free water. As the concentration of α-tocopherol increased from 0 to 1500 ppm, the consumption of headspace oxygen and the formation of volatiles decreased, whereas the contents of lipid hydroperoxides did not decrease in the linoleic acid-water system. The mass to charge ratios (m/z) of volatiles in linoleic aciddeuterium oxide were significantly higher than those with deuterium oxide-free water. Generally, the presence of α-tocopherol decreased the mass to charge ratios (m/z) of volatiles including pentanal, hexanal, t-2-heptenal, and 2-octenal, implying that α-tocopherol may be involved in the aldehyde formation from lipid oxidation.