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1.
The cyclone stickiness test (CST) technique was applied to measure the stickiness temperature and relative humidity of whey, honey, and apple juice powders. A moisture sorption isotherm study was conducted to analyze the surface moisture content of whey powder. The glass transition temperatures of the sample powder were analyzed using differential scanning calorimetry (DSC). The stickiness results of these products were found within 20°C above their surface glass transition temperatures, which is well within the normal temperature range for glass transition in general. The results obtained by the CST technique were found consistent with DSC values.  相似文献   

2.
The cyclone stickiness test (CST) technique was applied to measure the stickiness temperature and relative humidity of whey, honey, and apple juice powders. A moisture sorption isotherm study was conducted to analyze the surface moisture content of whey powder. The glass transition temperatures of the sample powder were analyzed using differential scanning calorimetry (DSC). The stickiness results of these products were found within 20°C above their surface glass transition temperatures, which is well within the normal temperature range for glass transition in general. The results obtained by the CST technique were found consistent with DSC values.  相似文献   

3.
The objective of the present work was to study functional and thermal properties of reineta (Brama australis) frozen meat, analysed by water retention capacity (WRC), gel forming capacity (GFC), texture, emulsifying capacity and differential scanning calorimetry (DSC). For this study, reineta fillets were obtained and extracted by the same conditions, and cutted, packaged, frozen and stored at -18 degrees C and -30 degrees C for 7 months. The results obtained, showed that there were no signifficant differences in the responses to thermal treatment for all the specimens. For samples frozen at -18 degrees C and -30 degrees C, the protein contents were 23.5 + 0.0 and 25.4 + 1.0%, respectively. The WRC values were 0.45 + 0.1 and 1.59 +/- 0.0 g water/g protein, respectively. The gel forming capacity was only present in the fresh samples, whereas the frozen stored ones only form protein aggregates. The emulsifying capacity was between 960 and 1400 g oil / g protein, and the storage time increased this value. The miosin denaturation temperature (Td) and denaturation enthalpy (?H), obtained by DSC, fluctuated between 39.2 +/- 0.5 to 44.8 +/- 0.8 degrees C and 1.12 +/- 0.3 to 0.52 +/- 0.2 J/g, respectively. The actina values were between 71.0 +/- 0.6 to 75.3 +/- 0.5 degrees C and between 0.5 +/- 0.1 to 0.7 +/- 0.1 J/g. Cooperativity decreased as the storage time increased. This is showing a certain degree of protein displacement. The values found by thermal analyses showed a direct relationship with the functional properties, both decreasing with storage time.  相似文献   

4.
Burcu Çabuk 《Drying Technology》2013,31(10):1223-1233
In this study, whey protein isolate-pullulan (WP/pullulan) microspheres were developed to entrap the probiotic Lactobacillus acidophilus NRRL-B 4495 by spray-drying technique. Microcapsules were analyzed for physicochemical characteristics including morphology, particle size, moisture content, water activity, dissolution time, and color properties. Results revealed that microcapsules were spherical in shape and obtained particle sizes between 5 and 160 µm, with an average size of around 50 µm. Blending pullulan with WP provided enhanced survival of probiotic bacteria during spray drying with a final viable cell number of 8.81 log CFU/g of microcapsule. Encapsulated probiotics were also found to have significantly (p ≤ 0.05) higher survived cell numbers compared to free probiotics under detrimental gastrointestinal conditions. Moreover, dissolution analysis suggested that protein-polysaccharide powdered microcapsules showed pH-sensitive dissolution properties in simulated gastric juice and simulated intestinal juice.  相似文献   

5.
考察了甘蔗糖蜜替代昂贵葡萄糖作为碳源、乳清粉替代大部分酵母粉作为氮源时,对Actinobacillus succinogenes NJ113发酵制备丁二酸的影响。血清瓶厌氧发酵结果证明:对照组(葡萄糖40 g/L)的丁二酸产量仅为26.04 g/L,而以糖蜜为碳源(以总还原糖计算为40 g/L)时,丁二酸产量达到28.27 g/L,比对照组提高了8.57%。在此基础上,以糖蜜为碳源、不同比例的乳清粉和酵母粉为混合氮源发酵制备丁二酸,确定了糖蜜、乳清粉和酵母粉混合使用的最佳浓度分别为40 g/L、8 g/L和2 g/L。此外,在3 L发酵罐体系中添加40 g/L糖蜜、8 g/L乳清粉、2 g/L酵母粉进行发酵试验,实验结果证明:丁二酸终产量达到32.54 g/L,收率达到81.13%。  相似文献   

6.
The applicability of the spray‐dried whey for the production of reduced‐calorie mayonnaise‐type emulsions was studied. Whey was used as a stabilizing/emulsifying agent and as a fat‐replacement component. Whey powder was spray‐dried at 130, 140, and 180 °C. As control sample, 80% w/w standard fat emulsion was prepared. Mayonnaise‐like fat‐reduced emulsions contained 65% w/w of fat and 15% w/w of three distinct types of whey. The destabilization of the emulsions was investigated within 7 days of storage by scanning the samples with laser light. Backscattering, Turbiscan stability index, elasticity index, and macroscopic viscosity index were determined. The most stable emulsion contained whey powder spray‐dried at 180 °C. The emulsion made with whey powder spray‐dried at 130 °C was less stable than that with 180 °C spray‐dried whey, but it was more stable than the control and the one with whey spray‐dried at 140 °C.  相似文献   

7.
Abstract

The objective of the present study was to investigate the effect of inlet air temperature of spray drying and different combinations of carrier agents (maltodextrin (MD), gum Arabic (GA), modified starch (MS), and whey protein concentrate (WPC)) on the physicochemical characteristics of spray-dried whey powder, enriched with vitamin D3 to improve its usage as a functional ingredient. Firstly, vitamin D3 was nanoencapsulated by nanoliposome prepared with egg yolk lecithin, sesame oil, and glycerol through thin-film dispersion method. The mean particle size of prepared nanoliposomes was 140?nm. Then, the prepared nanocarriers loaded with vitamin D3 were added into the feed solution and dried through spray dryer. The effect of carrier agent types and inlet air temperature on the physicochemical (moisture content, solubility, porosity, color, and powder yield) and microstructure properties of obtained spray-dried powders were investigated. The optimal carrier agents and condition of spray drying were selected by Taguchi design. Our results showed that the inlet air temperature and carrier agent had significant effects on the characterization of powders. Powders produced by 2% WPC, 3% MS, and 25% MD at 170?°C inlet air temperature showed the highest powder yield (96.4%). Also, the morphology of powders was affected by carrier agent types; increase in MD concentration in feed solution causes to create smoother and spherical spray-dried powder particles.  相似文献   

8.
The surface tension of freshly created food protein powder isolates was measured in aqueous solutions as a function of concentration, hydrolysis, and temperature. The surface tension of the solutions was measured immediately to best predict their surface-active behavior in a spray-drying scenario, where instantaneous values are more relevant than equilibrium surface tension measurements. Whole whey protein, hydrolyzed whey proteins (degrees of hydrolysis of 4, 9.5, 12, 17, and 20.2%), soy protein, pea protein isolates, and gelatin powders were diluted in a range of concentrations (0.04–2 g/L) and their surface tension values were reported at 23 ± 1°C. It was found that at higher concentrations hydrolyzed whey proteins at degrees of hydrolysis of 9.5 and 12%, and soy protein isolates in particular, showed excellent surface activity (shown through a decrease in surface tension) compared to nonhydrolyzed whey protein and gelatin. When comparing the influence of the degree of hydrolysis of whey proteins, the reverse was observed at lower concentrations (0.04–0.1 g/L), with the nonhydrolyzed whey protein reducing surface tension values more effectively than their hydrolyzed counterparts.

Additionally, the protein solutions (2 g/L) were maintained at higher temperatures of 40, 50, and 60°C and the surface tension values were measured. There was a general improvement of surface activity of proteins indicated by the reduced surface tension of solutions at these temperatures compared with the pure water values. The protein solutions were also spray dried with maltodextrin (MD30) and the powder particle surface composition and structures were analyzed via X-ray photoelectron spectroscopy and scanning electron micrography. There was a trend of correlation between the surface activities of protein in solution with that of the surface composition of protein found on the powder particles. However, there were morphological indicators that corresponded well to the amount of protein present on the surface.  相似文献   

9.
High‐intensity pulsed electric fields (HIPEF) is an emerging non‐thermal food preservation technology which has the potential to pasteurize pumpable liquid foods. Its application is being studied to evaluate it as potential alternative or complementary process to thermal pasteurization. Orange juice‐milk beverage with added bioactive components is a ready‐to‐drink beverage developed as an alternative to traditional soft drinks. In the present work, two HIPEF treatments (35 and 40 kV/cm) and six different treatment times (from 40 to 180 µs) were evaluated to assess their effect on the fatty acid profile of an orange juice‐milk beverage fortified with n‐3 fatty acids and oleic acid. The effect of HIPEF treatment on various physicochemical properties of the beverages: pH, °Brix, hydroxymethylfurfural or peroxide index was also determined. After HIPEF treatment, non‐significant changes in the contents of saturated fatty acids, monounsaturated fatty acids or polyunsaturated fatty acids were observed. Neither peroxides nor intolerable levels of furfurals were detected. Only a small reduction in fat content (p <0.05) was found. In conclusion, HIPEF can be proposed as an alternative preservation technology due to these minimal changes which are negligible from the nutritional point of view.  相似文献   

10.
The effects of inlet temperatures of 125, 150, 175 and 200 °C and maltodextrin levels at 3, 5, 7 and 9% on the physicochemical properties, total phenolic content (TPC) and 2,2-diphenyl picryl hydrazile (DPPH) scavenging activity of spray dried amla juice powder were studied. Moisture content and hygroscopicity of powder were significantly affected by inlet temperature and maltodextrin level. However, an increase in the level of maltodextrin did not significantly affect the bulk density and water solubility index (WSI). An increase in drying temperature and maltodextrin concentration decreased the free radical scavenging activity of the powder. Morphological study revealed that at higher inlet temperatures the spray dried powder had small sized particles that were densely packed. Spray dried amla juice powder made with 7% maltodextrin and processed at 175 °C inlet temperature had less hygroscopicity, acceptable color and potent free radical scavenging activity.  相似文献   

11.
In this study, production of pomegranate juice powder using a spray dryer was investigated. To prevent stickiness, maltodextrin dextrose equivalent 6 (DE6) was used as a drying agent. While feed flow rate, feed temperature, and air flow rate were kept constant, air inlet temperature (110–140°C), percentage maltodextrin (MD; maltodextrin dry solids/100 g feed mixture dry solids; 39.08–64.12%), and feed mixture concentration (19.61–44.11 °Brix) were chosen as the independent variables. Product properties investigated included moisture content, hygroscopicity, anthocyanin content, color change, solubility, bulk density, total phenolics content, antioxidant capacity, and sensory properties. The products were produced with high yield (86%) and high antioxidant activity (77%). MD and drying temperature were found to be the most important variables in production of pomegranate juice powders. Because total color change (ΔE), bulk density, antioxidant capacity, and powder yield were affected strongly by the independent variables, these parameters were used in optimization of the process. The optimum temperature, feed mixture concentration, and percentage maltodextrin were 100°C, 30.8 °Brix, and 53.5% MD, respectively. This study revealed that by applying these optimal conditions, pomegranate juice powder with a 55% dry solids yield, 9.78 total color change, 0.35 g/mL bulk density, and 57.8% antioxidant capacity were produced.  相似文献   

12.
30%醚菌·啶酰菌SC防治红地球葡萄白粉病药效试验   总被引:1,自引:0,他引:1  
陈卫民  张映合  郑运 《现代农药》2011,(5):51-52,56
30%醚菌·啶酰菌SC是醚菌酯和啶酰菌胺的混合制剂,对葡萄白粉病防治效果较好。2010年6月在新疆伊犁河谷红地球葡萄种植园进行了药效试验。结果表明,30%醚菌·啶酰菌SC 1000倍液对红地球葡萄白粉病的防效最好,第2次药后7 d的防效达到了85%,明显高于30%醚菌·啶酰菌SC 2 000倍液和12.5%烯唑醇WP 2 500倍液的防效。  相似文献   

13.
沿江地区水稻穗颈瘟关键防控技术的研究   总被引:1,自引:0,他引:1  
防治穗颈瘟的配套关键技术是推广种植抗稻瘟病或耐病的水稻品种;掌握穗颈瘟防治的最佳适期,即在水稻破口抽穗5%~10%时突击用药;隔5~7 d再用药1次;防治方法、药剂及用量分别为25%吡唑醚菌酯EC 70 mL、45%肟菌己唑醇WG 20 g、10%嘧菌酯CS 90 g、20%三环唑WP 100~120 g、20%井·烯·三环唑WP 150 g。提倡低容量喷雾、推广弥雾机或低水量细喷雾,水量少,浓度高,雾滴细,粘着力强,效果好。  相似文献   

14.
The effect of juice extraction conditions on the quality of haskap berries (Lonicera caerulea L.) dried at different temperatures (60, 100, and 140°C) was investigated. The conventional juice extraction (process A) consisted of a two-press process, where thawed berries were pressed, and osmotic treatment was applied before pressing again. This was compared with a modified extraction (process B), which applied osmotic treatment during fruit thawing and only one press was used for extraction. The quality parameters investigated included moisture content, pressed berry yield, extraction loss, drying yield, total anthocyanin content (TAC), vitamin C content, and the rehydration characteristics of the final dried berries. Pressing the berries to 70% juice yield resulted in a higher pressed berry yield and better physicochemical quality in the pressed product. The yield was 26.39 and 28.92% in the conventional and modified extraction, with moisture contents of 70.32 and 77.75%, respectively. The TACs of pressed berries from extraction processes A and B were 24.62 and 33.03?mg C-3-G g?1 DW and the vitamin C contents were 14.14 and 36.18?mg/100?g, respectively. Drying at 60°C until 25% moisture content was better than at higher temperatures, resulting in a better quality dried product. It revealed drying yields of 45.32 and 52.75%, TACs of 4.00 and 4.30?mg C-3-G g?1 DW, vitamin C contents of 2.97 and 4.91?mg /100?g, and rehydration ratios of 2.22 and 2.37 from processes A and B, respectively. Process B with the one-step extraction is recommended for higher pressed berry yield, higher drying yield, and enhanced quality of the pressed and dried products. It is also a more efficient process, in terms of time, cost, and energy.  相似文献   

15.
The aim of this work was to obtain a new stable food product from cashew apple juice encapsulated by spray-drying technique using chitosan–whey protein isolate systems. The materials were evaluated according to their physicochemical stability during storage at different conditions and characterized with respect to their particle size distribution and structure. Encapsulated commercial and natural juices showed homogenous and unimodal particle size distribution with diameters ranging from 0.2 to 5.0 μm and from 0.2 to 40.0 μm, respectively. Both juices demonstrated higher physicochemical stability for vitamin C and color measurements than their respective non-encapsulated juices. X-ray diffractograms evidenced that the powder juices after the 140th day of storage were still in amorphous state. These results indicate that the new product was effective in protecting sensitive compounds present in the food matrix and it was also able to remain stable throughout the study period.  相似文献   

16.
Kluyveromyces fragilis was cultivated batchwise in an open pond rectangular bioreactor at 30°C, 2vvm of aeration, under non-sterile conditions and uncontrolled pH. The culture medium contained 7% cheese whey powder, 0.25% KH2PO4, 0.5% (NH4)2SO4 and was adjusted to an initial pH of 4.0 with phosphoric acid. The lactose was almost completely consumed after 16 h and COD reduction attained 80% after 64 h. The maximum suspended solids concentration obtained was 11.7 g/L. The cheese whey which had initially low protein and high lactose contents was converted by this system into a high protein and low lactose carbohydrate product.  相似文献   

17.
Frémont L  Gozzelino MT  Linard A 《Lipids》2000,35(9):991-999
This experiment was designed to evaluate the effects of dietary red wine phenolic compounds (WP) and cholesterol on lipid oxidation and transport in rats. For 5 wk, weanling rats were fed polyunsaturated fat diets (n−6/n−3=6.4) supplemented or not supplemented with either 3 g/kg diet of cholesterol, 5 g/kg diet of WP, or both. The concentrations of triacylglycerols (TAG, P<0.01) and cholesterol (P<0.0002) were reduced in fasting plasma of rats fed cholesterol despite the cholesterol enrichment of very low density lipoprotein + low density lipoprotein (VLDL+LDL). The response was due to the much lower plasma concentration of high density lipoprotein (HDL) (−35%, P<0.0001). In contrast, TAG and cholesteryl ester (CE) accumulated in liver (+120 and +450%, respectively, P<0.0001). However, the cholesterol content of liver microsomes was not affected. Dietary cholesterol altered the distribution of fatty acids mainly by reducing the ratio of arachidonic acid to linoleic acid (P<0.0001) in plasma VLDL+LDL (−35%) and HDL (−42%) and in liver TAG (−42%), CE (−78%), and phospholipids (−28%). Dietary WP had little or no effect on these variables. On the other hand, dietary cholesterol lowered the α-tocopherol concentration in VLDL+LDL (−40%, P<0.003) and in microsomes (−60%, P<0.0001). In contrast, dietary WP increased the concentration in microsomes (+21%, P<0.0001), but had no effect on the concentration in VLDL+LDL. Cholesterol feeding decreased (P<0.006) whereas WP feeding increased (P<0.0001) the resistance of VLDL+LDL to copper-induced oxidation. The production of conjugated dienes after 25 h of oxidation ranged between 650 (WP without cholesterol) and 2,560 (cholesterol without WP) μmol/g VLDL+LDL protein. These findings show that dietary WP were absorbed at sufficient levels to contribute to the protection of polyunsaturated fatty acids in plasma and membranes. They could also reduce the consumption of α-tocopherol and endogenous antioxidants. The responses suggest that, in humans, these substances may be beneficial by reducing the deleterious effects of a dietary overload of cholesterol.  相似文献   

18.
  . Ibano  lu 《Drying Technology》1999,17(1):237-333
Tarhana, a traditional Turkish fermented yogurl-wheat mixture used in soups, was subjected to dilute acid hydrolysis in 0.5 M HCL (40% dry matter) at 55°C for 4 hours followed by simmering for 10 minutes. The resulting slurry was dried using a laboratory scale spray dryer. Water absorption index (WAI), water solubility index (WSI) and viscosity of spray dried tarhana powder were investigated. The WAI and WSI values for spray dried tarhana powder were found as 1.2 g gel/g dry tarhana powder and 70%, respectively, whereas these values for control sample were 4.0g gel/ g dry tarhana powder and 20% The viscosity of spray dried tarhana soup was found as 100 cp whereas the value for the control sample was 800 cp. When the soups were subject to sensory analysis, panelists found significant differences between the control and spray dried tarhana soups in terms of taste, mouth feel and overall acceptability in favor of the control sample.  相似文献   

19.
In this study, the effect of processing and storage time on the vitamin C and lycopene contents was evaluated. Guavas were washed, cut in quarters, blanched, pulped and the pulp pasteurized. The pulp was used for the production of nectar: guava pulp, sugar and water were mixed in 5:3:12 proportions, and the mixture was pasteurized, poured while hot into 125 mL glass jars, and cooled rapidly to 25 degrees C. The production of nectar from fresh guava reduced vitamin C, lycopene and titratable acidity, by contrast soluble solid and pH increased significant. Vitamin C content from 168.9 to 62.3 mg/(100 g fresh weight), and lycopene content from 3.55 to 1.35 mg/(100 g fresh weight) (p < 0.001 in both cases. After 240 days at 10.0 +/- 2 degrees C, no further statistically significant change in lycopene and soluble solid content was observed (p > 0.05). Storage time did affect vitamin C, pH, and titratable acidity content, vitamin C content fell by 89.3% to 6.67 mg/(100 g fresh weight) (p < 0.001). Based on this study, guava nectar storage at 10 degrees C retained 46% of the content of vitamin C for 120 days.  相似文献   

20.
This work deals with formulation and drying of a newly developed functional food. A watermelon and carrot juice mixture in the ratio 70:30 by volume was fermented at 37°C with Lactobacillus acidophilus to produce an innovative non-dairy-based food formulation with good flavor and high nutritional value. Viable count, pH, titrable acidity, protein content, and reducing sugar were measured during fermentation. The probiotic juice was spray dried at air temperature of 120 to 160°C and flow rate of 2.0 to 5.0 mL/min. Maltodextrin concentration of 10 to 15% by weight was used as an additive. Response surface methodology (RSM) was employed to optimize the drying process conditions. Physical properties (e.g., moisture content, density, porosity, and yield), biological properties (e.g., viability and lycopene and beta carotene content), and solubility data were examined as the response variables. Elevated temperatures and longer exposure times at lower feed rate reduced viability and lycopene and beta carotene content of the dried powder. Increased atomization pressure increased the cohesiveness but decreased flowability of the dried powder because the particle size was lowered. The probiotic powder was further analyzed using scanning electron microscopy (SEM) and differential scanning calorimetry (DSC).  相似文献   

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