de Borba, Veronica SimoesSilveira, Cinthia OrtizAlves, Janaina BarretoGrupelli, Victoria Marques...
7页
查看更多>>摘要：Pasta that undergoes the cooking exhibits several structural changes that can mainly affect protein and starch availability. In this study a central composite rotatable design (CCRD) 2(2) was applied to find the best cooking times and pasta:water ratios to prepare commercial semolina pasta (spaghetti) to increase RS levels. Time intervals applied to cooking ranged from 7 to 13 min while the pasta:water ratio ranged from 1:33 to 1:4 (m v(-1); g mL(-1)). Composition of the spaghetti samples was also determined. Cooking times strongly influenced RS formation and water absorption (WA) capacity, since there was mean decrease of 17% in WA and increase of 164% in the RS content when both extreme points (-1.41 and + 1.41) of the experimental design where applied. Protein and ash contents also affected the RS level. Cooking time between 7 and 10 min and pasta:water ratios (from 1:4 to 1:10, m v(-1)) enabled satisfactory RS contents (from 72.2 to 138.0 mg g(-1)), which should improve the functional fiber content in the pasta.
查看更多>>摘要：Mechanical and chemical structure changes of cooked rice during oral processing is complex and dynamic. Limited attention has been paid to link the oral processing of rice with its eating quality. In this work, a texture analyzer equipped with a multiple extrusion cell probe was used to simulate oral processing which can monitor the changes of force and work to evaluate the eating quality of rice. Cooked rice (30 g) and 3.6 mL simulated saliva containing 0.01 g low-temperature a-amylase (2000 U/g) were added into the cell followed by 25 compression cycles. The results confirmed cooked rice structure can be divided into fast breakdown structure (Type I), slow breakdown structure (Type II), and unbreakable structure. In this method, both a-amylase and starch retrogradation can increase compression cycles to break Type I structure down. Furthermore, the present of a-amylase significantly decreased the total work as well as the work contributed to the breakdown of Type II structure and unbreakable structure, and increased the work contributed to the breakdown of Type I structure. Cooked rice after retrogradation needed more work to break the structure down including Type I and Type II structure and generated less reducing sugar leading to the deterioration of rice eating quality. Based on the above results, we assumed the breakdown of Type I structure was mainly controlled by rice size reduction, the unbreakable structure is mainly related to the undigested substance during chewing, and the breakdown of Type II structure is mainly controlled by the combination of rice size reduction and enzymatic degradation. Thus, this simulated oral processing test is useful for investigating the dynamic changes of cooked rice structure during chewing which will be a key area for rice eating quality evaluation in future.
查看更多>>摘要：Flaxseed powder is a widely used nutrient-rich food, valued for its flavor as well as its nutritional value. The effect of peeling on the flavor profiles of raw and microwaved flaxseed powder remains unclear. In this study, the volatile components of flaxseed powder were analyzed using solvent-assisted flavor evaporation combined with gas chromatography-mass spectrometry-olfactometry. Fifty-two odor-active compounds were identified, with flavor dilution (FD) factors ranging from 3 to 729. Hexanal, D-limonene, 1-hexanol, beta-phellandrene, alpha-phellandrene, and nonanal with Odor Activity Values (OAV >= 1), which could impart green-like, fresh-like, and mint-like notes, were the typical odorants in raw flaxseed powders. Microwaved powders had more intense roasted and woody notes than raw powders. Peeling treatment had a significant effect on the aroma of microwaved flaxseed powder, but caused only a slight change in the flavor profiles of the raw powders. The key aroma differences in the two kinds of microwaved powders were mainly due to the levels of 2-methylbutanal, 2-methylpyrazine 6-methyl-5-hepten-2-ol, 4-hydroxy-2,5-dimethylfuran-3-one, 2-ethyl-3,6-dimethylpyrazine, and 2-ethyl-3,5-dimethylpyrazine. This work provides a basis for the improvement of the aroma of flaxseed products.
查看更多>>摘要：The European Commission recently authorized the placing of haskap (Lonicera caerulea L.) berries as a novel food on the EU market. It has been suggested that these berries have several health beneficial properties, due to their considerable content of highly valuable secondary metabolites, such as anthocyanins, phenolic acids, iridoids and fatty acids. Herein, we report a dynamic streamlined extraction process for iridoids and anthocyanins with supercritical carbon dioxide and ethanol as modifier. In particular, we have focused on the iridoids loganic acid and loganin, as well as on different hydroxylation patterns of the anthocyanins. The developed multiple step extraction process leads to initial separation of lipids at low ethanolic concentrations (1 vol%), followed by partial extraction of iridoids at 10 vol% ethanol and ultimately to combined extraction of iridoids and anthocyanins at higher ethanol amounts (>10 vol%). The sequential extraction can be performed in a closed system by automated variation of two innocuous solvents, but uses higher solvent amounts. In comparison to conventional ethanolic extraction, the dynamic streamlined yielded 97% of iridoids and about 7% more anthocyanins.
查看更多>>摘要：The effects of soy protein isolate (SPI) in combination with transglutaminase (TGase) on the gel properties of Zhikong scallop (Chlamys farreri) adductor muscle were investigated. When 4 g/100 g SPI combined with 0.4 g/100 g TGase were added, the gel strength and water holding capacity (WHC) of heat induced Zhikong scallop adductor muscle gel was significantly improved. The textural profiles, such as hardness, cohesiveness, springiness and chewiness, reached their peaks as well. Although the whiteness continued to decrease with the increase of SPI content, TGase did not influence the whiteness of Zhikong scallop adductor muscle gel regardless of SPI levels. According to the results of LF-NMR, the free water was transformed into bound and immobilized water in gels containing SPI and/or TGase. SDS-PAGE showed that TGase would promote the cross-linking of SPI and Zhikong scallop adductor muscle protein, and offset the negative effects of excessive SPI. Further optical microscopy and SEM observed that the formation of the most compact network structure, which was caused by more inter- and intra-molecular cross-linking of proteins. The results suggested that the addition of 4 g/100 g SPI combined with 0.4 g/100 g TGase could effectively improve the gel properties of Zhikong scallop adductor muscle.
查看更多>>摘要：The aim of this study was to analyse the impact of tasting temperature on difference thresholds of aqueous solutions of sucrose, glucose and fructose. By using the forced-choice constant stimulus procedure, reference concentrations of 2 g/100 g and 5 g/100 g sucrose, and glucose and fructose solutions iso-sweet to 5 g/100 g sucrose were evaluated at 5 degrees C, 22 degrees C and 56 degrees C. Depending on reference concentration, Weber fractions for sucrose range from 0.07 to 0.09, and those for glucose and fructose from 0.05 to 0.08 and 0.04-0.07, respectively. Significantly higher Weber fractions were recorded at 56 degrees C, indicating that higher sample temperature reduces sensory sensitivity towards sweetness. This may be important for the development of sugar-reduced instant beverages.
查看更多>>摘要：This study was conducted to develop an efficient drying method for off-ground harvested almonds. The whole almonds of three varieties (Nonpareil, Monterey and Fritz) were dried in a column dryer at different temperatures (45, 50, 55 and 60 degrees C) and air velocities (1.0 and 2.0 m/s). The drying time ranged from 2.5 to 6 h. No cavity, no color change, no significant concealed damage and no deterioration of oil quality were observed under the tested conditions (p < 0.05). Page model was used to standardize the initial and final moistures of almonds for energy consumption calculation. The specific energy consumption of the drying process ranged from 7.01 to 19.05 MJ/kg under the tested conditions. The energies consumed for drying different almond components were calculated based on the moisture removal from each components during the drying of the mixture of in-hull almonds, in-shell almonds, kernels and loose hulls, which showed more than 60% of energy was consumed for drying the hulls, and only 20% was used for kernel drying. Therefore, freshly harvested almonds should be sorted based on their moisture levels and dried separately. The findings from this study provide an important guidance for drying off-ground harvested almonds with improved efficiency and ensured product quality.
查看更多>>摘要：This study aimed to investigate the effects of bioactive casein phosphopeptides (CPPS) (0, 0.1, 0.2, 0.3 and 0.5% (w/v)) on physico-mechanical, structural, antimicrobial and antioxidant characteristics of gelatin-based films. The results demonstrated that the addition of CPPs to gelatin films significantly decreased solubility and water vapor permeability (WVP) of the treatments G-CPP0.1, G-CPP0.2 and G-CPP0.3, but the optimal treatment was achieved in treatment G-CPP0.1 (4.46 x 10(-12) g (m s Pa)(-1) of WVP and 43.5% of solubility). The light transmittance decreased with increasing CPPs concentration in the films, achieving the lowest transmittance (0-11.2%) of UV light in the 200-350 nm range. Treatment G-CPP0.1 showed improved mechanical properties such as the highest TS (18.14 MPa) and EAB (84.1%). FTIR and DSC analysis indicated suitable interactions between gelatin and CPPS functional groups in the sample G-CPP0.1. Gelatin-CPPS films showed good inhibitory effects against the tested Gram-positive microorganisms (Staphylococcus aureus and Bacillus cereus) by increasing the concentration of CPP in the composite film. In addition, they presented effective antioxidant activity by DPPH test (2,2-diphenyl-1-picryl hydrazide). In general, the results showed that the gelatin-CPPS edible films with lower CPP concentrations (0.1-0.2% of CPP) could be potentially used in food packaging to ensure the quality of food products, due to their suitable physico-mechanical properties and enhanced bioactive characteristics.
de Oliveira Neves, Leandra N.Leal de Oliveira, Marcone A.
7页
查看更多>>摘要：A comparison of the capillary zone electrophoresis under indirect detection at ultraviolet region (CZE-UV) method with the traditional cryoscopic method for lactose hydrolysis process monitoring is proposed. Two different lactose enzymatic hydrolysis processes (in batch and sterile) were assessed. The hydrolysis levels obtained by the CZE-UV method differed statistically from those obtained by cryoscopy, at 95% confidence, showing variations up to 20% at the same time of processing. During sterile hydrolysis, 90% of lactose reduction was detected after 1 h by CZE-UV and after 3 h by cryoscopy. For in batch hydrolysis, the CZE-UV method indicated 50% of lactose hydrolysis after 3 h of processing, while the cryoscopic method did not identify such lactose reduction during the process simulation. Our results demonstrated that CZE-UV method is precise and reliable analytical method, acting as a good alternative for lactose hydrolysis process monitoring.
查看更多>>摘要：A cost-effective, portable, ultra violet assisted vertical re-circulatory depuration system (UVDC) was developed and its effect on microbiological, heavy metal and proximate composition of Black clam (Villorita cyprinoides) was investigated. The process of depuration was found to be effective in reduction of total viable count by 1.8 log cfu g-1. Escherichia coli were within the permissible limit and both Vibrio cholera and V. parahaemolyticus were absent. The concentrations of heavy metals (Cd, Pb and Cu) were found to decrease by 40.44%, 96.51% and 34.50% respectively at the end of 48 h of depuration in UVDC. Significant reduction in protein, lipid, ash and glycogen contents were observed after the depuration process. The portability and easy to assemble nature of the system further improves its applicability as an onsite depuration unit which could be effectively utilized by the smallscale clam fishers/farmers depending on polluted waters for enhancing their income and livelihood.
NSTL
Elsevier