Valme Garcia-Moreno, M.Sanchez-Guillen, Manuel M.Delgado-Gonzalez, Manuel J.Duran-Guerrero, Enrique...
9页
查看更多>>摘要：Oloroso Sherry Wine is a fortified Sherry wine obtained by oxidation and ageing in American oak barrels of 500 L-600 L. In this work, the study of the suitability of other types of woods for the ageing of these wines was carried out. To compare the characteristics of the alternative woods, an oloroso wine was aged in four groups of 16 L barrels made of French oak, Spanish oak, chestnut, as well as American oak as control, with intense and medium toasting. Phenolic and furanic compounds, organic acids, volatile compounds, color characteristics, total poly-phenol index and sensory analysis of wines aged for two months were analyzed. The results confirmed that the aged samples could be differentiated on the basis of their chemical composition, and that the use of alternative woods to age oloroso Sherry wines, and the level of wood toasting, had the potential to provide products with specific differences to the traditional aged in American oak. Furthermore, the organoleptic characteristics of these alternative wines were valued above a standard Sherry wine.
Muhialdin, Belal J.Algboory, Hussein L.Kadum, Hana
8页
查看更多>>摘要：This study evaluated the effects of Cyperus rotundus rhizomes aqueous extract on the shelf life of wheat bread. The aqueous extract strongly inhibited the growth of Aspergillus niger (78%), Penicillium spp. (89%) Bacillus subtilis (95%) and Bacillus cereus (90%). The C. rotundus extract had no significant (p >= 0.05) effect on the moisture content (44.2-45.7) and water activity (0.86-0.87) of the wheat bread, significantly (p<0.05) increasing the phenolic content from 7.22 to 37.95 mg g(-1) and decreasing the pH from 6.12 to 5.11. Fungal growth was observed on the treated bread after 11 days at 30 degrees C compared to 4 days for the control bread. However, the addition of the aqueous extract of C. rotundus affected the sensory attributes of the wheat bread but the bread was still considered acceptable by the trained panellists. In conclusion, the aqueous extract of C. rotundus rhizomes is a potential natural alternative to synthetic preservatives to extend the shelf life of wheat bread with high consumer acceptability.
查看更多>>摘要：Aroma compounds and sensory features of lactose free (LFM) and traditional (TM) Mozzarella cheese have been investigated during their labeled shelf-life. Acetoin and 2-heptanone characterized both types of cheese at the production time. During the shelf-life, a statistically significant increase in the amount of the volatiles coming from amino acid and fatty acid metabolism occurred in the LFM samples after 8 days of storage and, to a lesser extent, in TM cheese after 13 days of storage. As regard sensory analysis, milk odor and milk flavor descriptors characterized TM and LFM in the early stage of their shelf-life; bitter and acid taste and yoghurt odor descriptors characterized LFM after 8 days and TM after 13 days. The differences between the two cheese types can be attributed to the proteolytic activity of the lactase enzyme. As a result, the volatile aroma profile and the sensory quality should be taken into account for a proper shelf-life definition of Mozzarella cheese and a shorter shelf-life should be suggested for LFM than TM cheese.
查看更多>>摘要：Adulteration is a serious problem in the expensive edible oils, especially for sesame oil (SEO). SEO is widely adulterated with cheap edible oils such as rapeseed oil (RO). Therefore, developing a low-cost, practical, and rapid analytical method for detecting and quantifying such adulteration in SEO would be useful. A dielectric spectroscopy-based system in the range of 40 kHz-20 MHz was developed to detect SEO adulteration. The principal component analysis (PCA) model was developed for detecting the authentic SEO. Amount of adulteration was predicted by means of artificial neural network (ANN) and support vector regression (SVR). Out-of-sample validation indicated the radial basis function (RBF) kernel SVR model had the best performance with correlation coefficient (R) of 0.9604, mean absolute error (MAE) of 4.9888 (mL/100 mL) and Root Mean Square Error (RMSE) of 6.0129 (mL/100 mL) followed by the ANN model with R value of 0.9192, MAE of 6.4033 (mL/100 mL) and RMSE of 7.8072 (mL/100 mL). The results showed the developed technique as a simple and inexpensive tool has an acceptable capability for detecting RO impurities in SEO. However, further research is needed to find whether the developed system would be able to detect adulterations generated by other inexpensive edible oils in SEO.
查看更多>>摘要：This study evaluated the effect of different sugar smoking times on the flavour profiles of chicken drumsticks using an electronic nose (E-nose), electronic tongue (E-tongue), and headspace solid-phase microextraction gas chromatography-mass spectrometry (HS-SPME/GC-MS). The moisture content, water activity, pH, and L*-value decreased from 71.26% to 65.23%, 0.987 to 0.979, 6.66 to 5.36, and 61.84 to 52.34, respectively (P < 0.05). The a*-value and b*-value increased from 4.96 to 9.65 and 16.61 to 26.45, respectively (P < 0.05) with the increase in smoking times. Seventy-five volatile compounds were identified, and 18 volatile compounds were identified as key odour compounds and among them seven key volatile compounds with variable importance in projection (VIP) > 1 were detected. Principal component analysis of E-nose, E-tongue, and HS-SPME/GC-MS indicated that 3-, 4-, and 5-min smoking samples had similar odour and taste profiles. Sensory analysis indicated that the 4-min sample had increased overall acceptability. The correlation analysis of E-nose and key volatile compounds with odour activity value > 1 and VIP >1 confirmed that W1C, W3C, and W5C sensors were sensitive to aromatic compounds, and W2S sensor was sensitive to ketones. These results may provide guidance for smoked chicken producers to reasonably control flavour formation.
查看更多>>摘要：In this study, convolutional neural networks (CNN) strategy combined with mid-infrared (MIR) spectra is applied for sugar adulteration identification in honey. In order to acquire the variations from different classes as well as obtain a better interpretation of the model, a visualization of the CNN algorithm is employed for honey adulteration determination. All kernels are co-acted to explore subtle features by learning different weights and biases. The amplified or attenuated signals transformed by the kernels yield positive or negative effects to the model. Furthermore, the visualized features are implemented for spectroscopy interpretation. The overall results demonstrate that CNN is a promising method with improved accuracy over least squares support vector machines (LS-SVM) and partial least squares discriminant analysis (PLS-DA) especially for the market-obtained samples. Besides, this study supports the theoretical and practical foundation for CNN on the aspects of feature selection, visualization and model interpretation.
查看更多>>摘要：This research investigated the effect of temperature and relative humidity (RH) conditions during ethylene oxide (EtO) fumigation for inactivation of Salmonella and Enterococcus faecium NRRL B-2354 on whole black peppercorns. Black peppercorn samples were inoculated with a five-strain Salmonella cocktail or E. faecium inoculum. EtO (735.3 mg/L) fumigation was conducted at different treatment temperatures (46, 53, and 60 degrees C) and different RH levels (30,40, and 50%) for the inactivation of inoculated black peppercorn samples with different exposure times (2-180 min). The temperature, RH, and exposure time exhibit significant linear effects on microbial inactivation. Bacterial inactivation during EtO fumigation was described by the Weibull model with the R-2 > 0.70 and RMSE < 0.20 log CFU/g at all conditions. The concave upward trend of the Weibull model indicated a tailing effect. The inactivation data were also used to develop the response surface model as a function of temperature, RH, and exposure time to predict the reduction of Salmonella or E. faecium on whole black peppercorn during EtO fumigation. The developed models predicted log reductions with RMSE of 0.48 and 0.45 log CFU/g for Salmonella andE. faecium, respectively. Technical information for developing and validating EtO fumigation for whole black peppercorn could be estimated based on the developed model.
查看更多>>摘要：To investigate the influence of Lactobacillus plantarum on managing lipolysis and flavor generation of Staphylococcus xylosus and Saccharomyces cerevisiae, three strains, Lactobacillus plantarum 120 (Lp-120), Staphylococcus xylosus 135 (Sx-135) and Saccharomyces cerevisiae 31 (Sc-31), isolated from traditional fermented fish were cocultured in fish paste with and without the addition of tert-butylhydroquinone (TBHQ). For comparison, the groups without inoculation of Lp-120 were acidified by glucono-delta-lactone (GDL) to exclude the effect of acidogenesis by Lp-120. The results showed that Sx-31 exhibited the highest liberation of FFAs at 4911 mg/kg dry matter (DM), followed by Sx-135 (4661 mg/kg DM) under monoculture and acidic conditions. However, when co-inoculated with Lp-120, although the growth of Sc-31 was slightly promoted, its lipolytic activity declined dramatically as evidenced by the lowest FFA concentration of 3414 mg/kg DM, accompanied by decreased free fatty acid (FFA) oxidation. Furthermore, when cocultured with Lp-120, the growth of Sx-135 was remarkably inhibited, and the release of FFAs (3984 mg/kg DM) also showed a moderate decline, but FFA oxidation was at the highest level. The results suggested that during fermentation of fish with the mixed-culture of the three strains, the liberation and oxidation of FFAs mainly resulted from Staphylococcus xylosus, followed by Saccharomyces cerevisiae. However, Lactobacillus plantarum inhibited the lipolysis and flavor generation caused by Staphylococcus xylosus and Saccharomyces cerevisiae, especially Saccharomyces cerevisiae.
查看更多>>摘要：This study applied the ultra-performance liquid chromatography coupled with time-of-flight mass spectrometry metabolomics to investigate changes in the metabolites of fermented milk with novel probiotic Lactobacillus plantarum P9. The analysis of changes in viable counts and acidity during fermentation and storage indicated that the P9 strain fermented the milk effectively and reached a fermentation end point (pH 4.5) after 13.5 h. The fermented milk was relatively stable after 28-day of cold storage. These results suggested P9 was a suitable starter culture for fermented milk production. Significant differences were observed in the milk metabolome after fermentation and after different periods of cold storage. A total of thirty-five differentially abundant metabolites were identified, including 25 significantly increased and 10 significantly decreased metabolites in the fermented milk. These metabolites included fatty acids, peptides, carbohydrates, and other metabolites, some of them could offer functional attributes to the final products. No previous study has evaluated metabolomics changes of P9 during fermentation and storage. Thus, our data provide a valuable reference for the future development and improvement of fermented dairy products using the P9 strain.
查看更多>>摘要：The physicochemical, functional, thermal properties and in vitro digestibility of flours from germinated Bambara groundnut (BGN) were monitored over 72 h. In a time dependent manner, germination led to significant (p <= 0.05) increases in protein (26.1-28.79 g/100 g), dietary fiber components, digestible starch, in vitro protein digestibility (73.67-88.9%), calcium, magnesium, potassium, total phenolic content, and majority of the amino acids. Germination significantly decreased phytic acid, tannin and trypsin inhibitory activity. Protein solubility, oil and water absorption capacity, foaming capacity, emulsion stability and activity of BGN flour increased significantly with germination. Germination also modified the thermal and pasting properties of the flour. However, scanning electron microscopy did not reveal significant changes in starch granular structure. There were significant decreases in relative crystallinity (57.94-20.92%) as observed from the X-ray diffractograms. This study has demonstrated that germination significantly improved the nutritional, total phenolic content, functional and processing properties of BGN flour. This could encourage its utilization in food product development, particularly as a functional food ingredient.
NSTL
Elsevier