Mantı, the traditional Turkish food, was subjected to modified atmosphere packaging (MAP) to extend its refrigerated storage time. Beef, which is one of the main raw ingredients in mantı, is a highly perishable product. Therefore, it is essential that the microbiological effects of this product be analysed. The microbiological qualities of each mantı package were assessed by analysing raw mantı samples to determine the number of Lactobacillus spp. they contained, as well as the total anaerobic mesophilic microorganisms, the amounts of Staphylococcus spp., yeast and mould, the coliforms, Escherichia coli, Salmonella spp. and Clostridium perfringens and the total aerobic psychrophilic microorganisms. Salmonella spp. and C. perfringens were not detected in the raw materials or the packed samples, but the Lactobacillus spp. and total anaerobic mesophilic microorganism counts increased during cold storage. Growth of Enterobacteriaceae species in a modified atmosphere during the period in which the mantı is being stored must also be taken into account. The compositions of the MAP samples lasted for the maximum storage time of 126 days as opposed to 20 days in normal atmospheric packaging. In conclusion, more than 40% carbon dioxide (CO2) with nitrogen (N2) should be used in the mantı process.
The concentration of conjugated diene structures produced by the oxidation of glyceryl trilinoleate was measured spectrophotometrically. The test lipid was held at 5, 30, 40 and 50°C in air. The concentration was estimated using the molar absorption coefficient of conjugated methyl linoleate. The results showed that the concentration of conjugated diene structures was rapidly increased at higher temperatures. Rate constants were determined from the experimental results according to a chemical reaction model and its kinetic equations for the lipid oxidation process. Transient changes in the concentration of conjugated diene structures as calculated from the rate constant explained the experimental results well. The Arrhenius activation energy was 155 kJ/mol.
d-glucuronic acid (GlcA) and d-glucuronolactone (GlcL) were treated with subcritical aqueous ethanol in the range of 0% to 80% (w/w) at 180°C in order to examine the effect of ethanol on the interconversion between GlcA and GlcL. When GlcA was treated at higher ethanol concentrations, less GlcA disappeared and more GlcL was formed compared to treatments at lower ethanol concentrations. For comparison, in the treatment of GlcL at higher ethanol concentrations, disappearance of GlcL was slower and less GlcA was formed. The degradation and interconversion of GlcA and GlcL were kinetically analyzed under the assumptions of first-order kinetics in order to evaluate the rate constants for each process. The rate constants were smaller at higher ethanol concentrations. This was particularly manifested in the significantly low rate constants observed at ethanol concentrations higher than 60%. The treatments of GlcA and GlcL were also examined at 200°C, and the effect of ethanol at 200°C was similar to that at 180°C.
Surimi wash-water (SWW) contains a high concentration of protein resulting in a negative environmental impact and high disposal costs. Isoelectric point precipitation has been used for protein recovery from SWW. Here, we show an improved protein recovery method combining pH shift and heat treatment for Alaska pollock SWW. In a laboratory-scale experiment, a pH shift from neutral to pH 5 precipitated 63% of the SWW protein and subsequent heat treatment at 60°C precipitated almost all of the remaining protein. In a factory-scale experiment, the optimized pH shift and heat treatment yielded a 21% protein pellet with a 79% moisture content. The SWW protein gel thus obtained showed suitable quality as a surimi product as determined by the similar whiteness and strength as gel prepared from low-grade surimi. The optimized method combining pH shift with heat treatment improves the protein yield from SWW and prevents environmental pollution.
DNA extraction is critical for seafood authentication based on DNA techniques. In this study, eight extraction methods, including commercial kit, from three types of seafood (quick frozen, roasted, and canned products) were compared in terms of DNA yield and purity. The quantity and quality of extracted DNA were evaluated using the ratio A260/A280. Quality was also evaluated by two pairs of primers that could amplify two different sizes of DNA fragments respectively. For quick frozen samples, the results showed that the top three methods for DNA yield were the SDS method, TIANGEN GMO food DNA Extraction Kit, and TIANamp Marine Animals DNA Kit. For roasted samples, the top two methods for DNA yield were the SDS and improved CTAB methods. For canned samples, the top two methods for DNA yield were the SDS and phenol/chloroform/isoamylic alcohol methods. The differences between these aforementioned methods and the remaining methods were highly significant (P < 0.01). The DNA extracted from roasted and canned seafood could not amplify the 650 bp but amplified the 358 bp target fragment. This study determined the proper DNA extraction method for three types of seafood to facilitate seafood authentication.
The simultaneous microwave-assisted ethanol reflux extraction of flavonoids and saponins from Astragalus was studied. Response surface methodology (RSM) was used to develop predictive models for simulation and optimization of the extraction process. Based on the single factor test, the multivariate regression equation was obtained by the RSM of five-factors and five-levels, which designed from the Central Composite Circumscribed Design program. The response surface and contour lines were determined by using the yields of Astragalus flavonoids and saponins as response values. The optimum conditions of the microwave-assisted ethanol reflux extraction were obtained as follows: liquid to solid ratio of 22 mL/g, extraction temperature of 62°C, ethanol concentration of 64% (v/v), extraction time of 22 min, and microwave power of 590 W. The yields of Astragalus flavonoids and saponins reached as high as 25.63% and 0.98%, respectively. Multiple regression equation is extremely significant for the prediction of practical production.
Milled common Japonica rice was cooked using a newly developed superheated steam rice cooking machine and the volatile odor compounds of the steamed rice and of the steam generated during cooking were analyzed. At least 22 odorous compounds were found in the steam by GC-olfactometry, of which 13 were identified by GC-MS. Hexanal and (E,E)-2,4-decadienal, which are known odor compounds characteristic of cooked rice, were identified, and four compounds, including longifolene and 2-methoxyphenol, were newly identified in Japonica rice. The amounts of hexanal and (E,E)-2,4-decadienal in steamed rice, extracted with methyl tert-butyl ether, were essentially the same as in ordinary cooked rice. On the other hand, headspace analysis showed that the levels of odor compounds in steamed rice were less than 10% that of ordinary cooked rice. Only small amounts of odorants appear to be released from the surfaces of steamed rice grains.
Rosmarinic acid (RA), a polyphenolic compound abundantly found in the Lamiaceae family, has been shown to possess antioxidant and anti-inflammatory properties. In this study, we investigated whether it can promote energy expenditure in skeletal muscle cells. RA increased fatty acid oxidation and glucose utilization in C2C12 myotubes in a dose-dependent manner and increased the expression of Ca2+/calmodulin-dependent protein kinase kinase (CaMKK) and activated AMP-activated protein kinase (AMPK). CaMKK inhibitor attenuated the RA-induced AMPK activation and energy expenditure. Sirtuin1 (SIRT1) expression was enhanced by RA at both the gene and protein levels. We also observed that RA enhanced deacetylation of peroxisome proliferator-activated receptor γ coactivator-1α (PGC1α), accounting for the increase in energy expenditure-related genes. SIRT1 inhibitor attenuated the RA-induced PGC1α deacetylation and energy expenditure. Our findings suggests that CaMKK and SIRT1 play a role in the beneficial effects of RA on energy expenditure in skeletal muscle cells.
Meat homogenates and intestinal extracts were prepared from walleye pollack (Theragra chalcogramma) and white croaker (Pennahia argentata). Then, the proteolytic profiles of meat homogenate in the presence of the intestinal extracts were determined. The proteolytic activity in the intestinal extracts from walleye pollack was the maximum at 50°C and pH 8.53. The maximum activity was recognized also at 50°C when the intestinal extracts from walleye pollack were added to the meat homogenate prepared from white croaker, while it was at 60°C when the intestinal extracts from white croaker were added to the meat homogenate prepared from walleye pollack. These results suggest that the proteolytic profile is predominantly attributable to proteolytic enzymes and not to the substrate species of myosin heavy chain. These findings are useful for managing heating conditions in the industry in order to avoid modori and thus improve the quality of surimi-based products.
The amylopectin long-chain rice “Konayukinomai” (MAI) is high in resistant starch (RS). In this study, we confirmed that fine rice flour for bread making could be obtained using MAI, and compared the results to the high-amylose cultivar “Koshinokaori” (KOR) and the conventional cultivar “Koshihikari” (HKR). MAI bread contained larger amounts of RS and slowly digestible starch (SDS) than that of HKR or KOR, and the RS content of MAI was easily changed by retrogradation and re-gelatinization of the starch. In a clinical trial with healthy volunteers, MAI and KOR breads could prevent abrupt increases in blood glucose and showed low glycemic index (GI) values compared to HKR bread. From the above results, we propose that SDS and RS prevent increases in blood glucose, and consider MAI to be a promising rice cultivar as a nutraceutical food material for the prevention of lifestyle-related diseases.
We performed random-centroid optimization to determine the optimum preparative method for glycation of chicken myofibrillar proteins (Mfs) with the strongest antioxidative activity against hydroxyl radicals (·OH) and with more than 60% solubility in low ion strength medium. Four factors, temperature, relative humidity (RH), reaction time, and quantity of maltose, were selected and 13 vertices were obtained. The examination was carried out according to each vertex and the optimum conditions were sought, resulting in 57.4°C, 37.3% RH, 37.2 h of reaction time, and a maltose mixing ratio of 5.43 for Mfs (w/w). The ·OH-averting capacity (HORAC) was measured as 7.8 ± 1.0 µmol of gallic acid (GA) equivalent/g of protein. Moreover, the optimized glycated chicken Mfs could form a gel by a 30-min heating at 90°C, and this gel maintained the antioxidant ability. Its HORAC was 4.4 ± 1.7 µmol of GA equivalent/g of protein.
The aroma concentrates of three different cultivars of vanilla bean were prepared by combining the solvent extraction and solvent assisted flavor evaporation (SAFE) techniques. Aroma extract dilution analysis (AEDA) of the volatile fraction revealed 36 odorants, including nine newly identified vanilla odorants, which were identified or tentatively identified from the 49 odor-active peaks with FD factors between 41 and 49. Based on these results, it was proposed that the potent odorants, except for vanillin, were able to influence the characteristic flavor of vanilla beans from different growing regions.
Winter savory extract (WSE) is composed of volatile and non-volatile fractions (WSV and WSN, respectively). We have reported that winter savory volatiles such as WSV, carvacrol or thymol (primary and second components in WSV, respectively) contributed to changes in body surface temperature and core body temperature (BST and CBT, respectively) in humans. In this study, we examined WSN, whose effects on body temperature are unclear, and the mixture of WSN with winter savory volatiles, which likely have a different mechanism of action compared with WSN. WSN ingestion inhibited the decrease in wrist and finger BST, whereas mixtures increased the affected skin parts. Furthermore, the onset of effects at the periphery after mixture ingestion was faster than that after WSN ingestion. These results suggest that volatiles added to WSN greatly influence not only the balance of heat production and transfer, but also the rapid onset of effects at the periphery.
Effect of hot water extraction on composition and antioxidant activity of prodelphinidins (PDs) from two cultivar bayberry leaves (Biqi and Dongkui) were studied. Composition of PDs were analyzed by NPHPLC-DAD/UV-ESIMS. Dimers to tetramers were separated and each polymers consisted of more than one compounds. Oligomer contents in Biqi extract were considerable, just like high polymers in Dongkui extract. Most dimers (∼4 mg/g) and trimers (∼2.2 mg/g) of Biqi was extracted at 75°C while most tetramers (∼1.7 mg/g) and other polymers (∼11 mg/g) was extracted at 100°C. The highest content of dimers (∼4 mg/g) in Dongkui existed at 50°C. Other polymers showed highest content nearly at 100°C. Antioxidant results (DPPH and FRAP) proved that hot water extract possessed antioxidant activity. In a word, composition of PDs were affected by hot water extraction. Proper extraction condition and materials should be chosen according to your purpose.
Water absorption (%) in small wheat flour samples must be determined in many flour experiments. In general, a farinograph is used to determine the water absorption, but this method requires large amounts of wheat flour (300 g). In this study, water absorption in a small amount of wheat flour (10 g) was determined using a mixograph. The water absorption measured using the mixograph was very similar to that measured using a farinograph and 300 g of wheat flour. Thus, the water absorption in a small amount of wheat flour can be accurately measured using a mixograph.
In the present study, we investigated the inhibitory effects of four tea catechins, including (−)-epicatechin (EC), (−)-epigallocatechin (EGC), (−)-epicatechin gallate (ECg) and (−)-epigallocatechin gallate (EGCg), on angiotensin converting enzyme (ACE) activity in vitro. Each catechin treatment significantly reduced the ACE activity with the order of potency being EGCg > ECg > EGC = EC. The addition of 1 mM borate significantly recovered the reduced ACE activities by tea catechins, suggesting that hydroxyl groups at the B-ring or at a galloyl moiety play an important role in the ACE-inhibitory mechanism. The covalent modification of ACE by tea catechins was also observed by a redox-cycling staining experiment. A Lineweaver-Burk plot indicated that EGC and ECg were non-competitive inhibitors. The galloylated catechins might more potently inhibit ACE activity in an allosteric manner through the interaction of the galloyl moiety with the non-catalytic site of ACE.