教学课程资源库 更多>>

关键词： gelatine gel   candelilla wax   rice starch   lysozyme   composite gel   green tea extract  

摘要： Research background. The use of gel-based systems as a novel method for the delivery of natural antimicrobial, antioxidant and bioactive compounds is a developing innovative solution for the food industry. This research aims to develop multifunctional active edible gels based on gelatine and its composites with improved mechanical properties. Experimental approach. Antilisterial and bioactive composite gels showing different physical and active properties from classical gelatine gel were developed by loading lysozyme and green tea extract into gelatine/starch and gelatine/wax composite gels. Mechanical properties, swelling profiles, colour, release profiles, and antimicrobial and bioactive properties of the gels were characterised. Results and conclusions. Gelatine/wax gels showed 1.3 -to 2.1-fold higher firmness and cutting strength than gelatine and gelatine/starch composite gels that had similar firmness and cutting strengths. Work to shear of both composite gels was 1.4 -to 1.9-fold higher than that of gelatine gel. The gelatine/starch gel showed the highest water absorption capacity. Green tea extract reduced soluble lysozyme in all gels, but composite gels contained higher amount of soluble lysozyme than gelatine gel. All the gels with lysozyme inhibited Listeria innocua growth in the broth media, while green tea extract showed antilisterial activity only in gelatine/wax gels. Gels with green tea extract showed antioxidant, antidiabetic (alpha-glucosidase and alpha-amylase inhibition), antihypertensive (angiotensin-converting enzyme inhibition) and antiproliferative activities (on Caco-2 human colon carcinoma cells). However, gelatine and gelatine/wax gels showed the highest antioxidant and antidiabetic activity. The gelatine/wax gels prevented phenolic browning, while green tea extract in other gels showed moderate or extensive browning. Novelty and scientific contribution. This work clearly showed the possibility of improving mechanical properties and modify

关键词： Growth promotants   Hair breed sheep   Muscle histochemistry   Collagen   Fatty acid profile   DFD meat  

摘要： Muscle fiber morphometry and physicochemical characteristics were evaluated in LT muscles obtained from entire male lambs treated with zilpaterol hydrochloride (ZH, 0 and 0.15 mg/kg body weight) and/or steroidal implant (SI, with and without trenbolone acetate/estradiol). ZH and SI acted synergistically to increase LT area, type-IIb fiber cross-sectional area and soluble collagen content, likewise to decrease metmyoglobin concentration and insoluble collagen content. Ash content and ultimate pH showed a decrease due to an antagonistic effect between ZH and SI. Content of total collagen, protein, fat, moisture, oxidized lipids and water-holding capacity were unaffected by ZH and SI. Supplemental ZH, but not SI, decreased all color parameters and tended to increase shear force. Overall, the SI implantation of male lambs followed by a ZH supplementation promoted greater LT hypertrophy, without affecting protein and fat content, and physicochemical characteristics in their meat.

关键词： Hazelnut milk   Ice cream   Rheology   Cox-merz rule   Sensory quality  

摘要： High pressure homogenized hazelnut milk (HM) as a functional food compound was incorporated into ice cream as a replacer of cow milk (0-25-50-75-100%) to investigate its effect on the rheological, textural, physical, functional, and sensory properties of ice cream. Rheological experiments showed that the water-holding properties, flow behaviors, and emulsifying capacity of ice creams were improved by increasing HM ratio (p < 005) due to the more developed structure and a higher degree of molecular connectivity. At higher HM concentrations, the reduced melting rates and retarded first dripping time values were observed (p < 005) for ice creams, exhibiting higher consistency, material stiffness values, total phenolic content and antioxidant activity. The usage of HM up to 75% concentrations in ice cream production improved the acceptability of the product enhancing their sensory parameters. The enrichment of ice cream with HM may help to enhance the functional, structural, and also nutritional characteristics of dairy products.

关键词： Microencapsulation   HPLC   GC-MS   Gelatin   Gum arabic   Carvacrol  

摘要： It has long been known that oregano herbs have wide uses and industrial applications due to their high antioxidant activities and other activities of the main essential oil compound, carvacrol, but these compounds are sensitive to oxidation. Gas chromatography-mass spectrometry (GC-MS) analysis was performed to identify the volatile compounds of Origanum onites L. (OOEO), and the main volatile component of OOEO was determined as carvacrol (69.60%). This study aims to develop OOEO-loaded microcapsules by complex coacervation using gum arabic (GA) and gelatin (GE) as wall materials and different concentrations of tannic acid (TA) as a cross-linker. The OOEO microcapsules cross-linked using 2% TA have the highest loading capacity, microencapsulation yield, and efficiency with 36.39%, 83.75%, and 89.61%, respectively. The Fourier transform infrared spectra of the complex coacervates showed characteristic carvacrol peaks, one of the main components of OOEO, indicating that OOEO was successfully encapsulated in the polymer matrix. Thermal gravimetric analysis data revealed that cross-linking with TA affects the thermal stability of the microcapsules attributed to electrostatic interactions between the microcapsule wall and TA. With increasing TA concentration, GE/GA-walled microcapsules exhibited decreased aggregation with increased particle size and absolute zeta potential. This new approach to the production of OOEO-loaded microcapsules provides a high yield strategy with improved physico-mechanical properties and antioxidant activities.

关键词： Basalt   composite   polyethylene   polypropylene   mechanical properties  

摘要： YThe influence of basalt filler on mechanical properties of polyethylene (PE)- and polypropylene (PP)-based composites, and the effect of basalt on heat resistance and inflammability of polymer composite materials were studied. The introduction of basalt into the composite increases its elasticity modulus. The best mechanical properties are observed when 40 parts by weight of basalt per 100 parts of low-density PE and high-density PE are introduced. At the same time, a slight decrease in the deformation at failure is observed in basalt-filled PE composites. Deformation before failure is reduced from 380% for original PE to 250% for the composite containing 40 mass of basalt per 100 parts of PE. In the case of PP, this tendency is not observed. Other mechanical characteristics of polymer composites slightly change with the introduction of basalt particles as a filler. Incorporating basalt into PE and PP influences the combustibility of composites: oxygen index increases 1.3 times compared with the unfilled polymers, self-burning time decreases more than 2 times, and the loss of mass during ignition in the air decreases 2.15 times for PE-based composite and 1.75 times for PP-based composite. All indicators of flammability vary additively to the content of basalt, which is a noncombustible material.

关键词： Honeydew honey   Heat   Ultrasound   Antioxidant and antibacterial properties  

摘要： The objective of this study was to examine the effect of different treatments on the physicochemical, antioxidant, and antibacterial properties of honeydew honey. Honeydew honey was subjected to heat treatment and 9 different ultrasound treatments. Our results showed that the following parameters were significantly changed: water content, pH, electrical conductivity, diastase activity, HMF content and water activity. The ultrasound resulted in an increase in the total phenol content and the antioxidant capacity (DPPH, FRAP, and ABTS tests) in comparison with the conventional thermal technique. In most cases, the samples subjected to ultrasound improved the antibacterial activity;the heat treatment resulted in a significant reduction of the antibacterial activity, and sample 4 (ultrasound 30 degrees C, 5 min) showed the best antibacterial activity. The ultrasound treatment, especially at lower temperatures, represents a technique that enables the preservation and improvement of the biological properties of honeydew honey.

关键词： Nutrition  

摘要： This work was planned to investigate the influence of polydextrose as a fat replacer on the properties of skimmed yogurt. So, five batches were prepared;full-fat yogurt (control) and four skimmed yogurt batches prepared with 0%, 1.0%, 2.0%, and 3.0% polydextrose, respectively. Addition of polydextrose had significant effects on pH values and acidity and skimmed yogurt with 3% polydextrose exhibited significantly (p <= .05) higher in the apparent viscosity, WHC, and lower in syneresis. The viable counts of Streptococcus thermophilus and Lactobacillus spp. in samples containing polydextrose remained above >10(6) CFU/g. Microstructure showed stronger and more stable gel structures in treatment with 3% polydextrose. No significant differences were noted between yogurt with 3% polydextrose and full-fat yogurt in sensory attributes except flavor. Higher sensory scores were observed for yogurt with 3% polydextrose. Thus, the addition of 3% polydextrose was sufficient to develop skimmed yogurt with desired properties. Practical applications In recent years, growing attention to diet and healthy food products. these products are lower or free in fat contents because of their nutritional values and health-promoting properties. Yogurt is the most popular fermented functional dairy product consumed by all ages worldwide. The addition of polydextrose as a fat replacer with the level of 3% to yogurt increased the viability of starters and enhanced the physical and sensory properties of the product. Finally, our study concluded that the addition of polydextrose proves the effectiveness and consumption of fat-free dairy foods. We can produce many fat-free cheeses, ice creams, and beverages for special cases.

关键词： Moisture changes   Semidry grinding   Rice grain property   Rice flour quality  

摘要： In this study, the effects of moisture changes on rice grain crack, volume and hardness during the semidry grinding process, as well as the damaged starch, microstructure, hydration, and pasting properties of rice flours prepared with different semidry grinding conditions were studied. Moisture changes of semidry grinding showed a "decrease-increase-decrease" pattern which represents hot-air treatment, tempering and drying process, respectively. With the moisture changes of semidry grinding, severe cracks occurred on the rice grains after hotair treatment, and the hardness of the rice grains decreased rapidly in the first 15 min of tempering. For rice flours, the hot-air treatment and tempering were beneficial to reduce the content of damaged starch, and the tempering process had the greatest influence on the hydration and pasting properties of the rice flours among the three processes of semidry grinding. Moreover, the drying process had a positive effect on thermal paste stability and the resistance of retrogradation of the rice flours. These findings indicated that the "decrease-increasedecrease" pattern of moisture changes during the semidry grinding process affected the rice flour qualities, and could be used to guide the semidry grinding production of specific rice flours.

关键词： Artisanal cheese   Ripening   Sensory acceptability   "Rala" culture   "Pingo" culture  

摘要： This study evaluated the influence of ripening time on the physicochemical properties and sensory acceptability of artisanal cheese from the Serro region (SAC), produced with different endogenous starter cultures ("pingo" and "rala") and ripened under two different conditions (room temperature without packing and 8 degrees C with vacuum-packed). The acceptability test was conducted at five ripening times with untrained judges (regular cheese consumers). Judges over 35 years old had 2.3-fold higher odds of liking cheese than judges from 22 to 35 and 2.7-fold higher odds than judges from 18 to 21 years. Males had almost two times higher odds of enjoyment than females. Cheeses produced with the pingo culture were more likely to be accepted by the judges than cheeses produced with rala culture, but only up to 17 days of ripening. Vacuum-packed cheese ripened at 8 degrees C was almost three times more likely to be accepted than unpackaged cheese ripened at room temperature. There were no significant variations in pH, acidity, moisture, and salt contents of cheeses produced with different starter cultures. Salt-in-moisture did not differ between starter cultures and ripening conditions. The SAC ripening conditions had a greater influence on sensory acceptability than the endogenous cultures used in manufacturing.

关键词： Leuconostoc mesenteroides   Exopolysaccharides   Physicochemical properties   Rheology   Fermented milk  

摘要： Studies regarding the effects of extracellular polysaccharides produced by high-quality Kefiran production strains on the quality of yoghurt products and the mechanism of action during fermentation and production of yoghurt products are scarce in the literature. However, these studies are highly significant in the development of starters for the yoghurt industry. In this study, a Leuconostoc mesenteroides XR1 strain that produced exopolysaccharides (EPS) was identified and isolated from kefir grains collected from Xinjiang, China. XR1-EPS has similar flocculation characteristics to xanthan gum and higher emulsifying activity than locust gum. A rheological test of the dairy product sample after fermentation of XR1 single bacteria proved that XR1-EPS can impart higher viscosity and elasticity to fermented milk. Results also showed that XR1-EPS can maintain the water-holding ability of the fermented milk and provide a positive thixotropic fluid. In this study, XR1-EPS was isolated in the laboratory for the first time and was shown to be useful as a natural organic additive that can replace chemical additives in dairy products.