干燥方式对蒸谷米品质的影响

以稻谷为原料,以蒸谷米水分含量、出米率、整米率、裂纹率、出饭率、膨胀率、蛋白质含量以及感官评定为评价指标,系统地比较微波干燥、低温干燥、热风直接干燥、分段干燥、三段缓苏干燥这5种不同的干燥工艺对蒸谷米品质的影响。结果表明:在5种不同的干燥工艺中,低温干燥的效果最好。即浸泡温度45℃,浸泡时间5h,浸泡压力150kPa,蒸煮温度100℃,蒸煮时间10min,干燥温度90℃,干燥时间30min所得蒸谷米品质最好。     

浸泡对早籼稻水分含量及蒸谷米品质的影响

以早籼稻为对象,通过改变浸泡时间和温度,测定分析浸泡条件对早籼稻的水分含量、蒸谷米VB1的含量以及蒸谷米品质的影响。结果显示,浸泡条件对蒸谷米品质影响明显,当浸泡温度为75℃、时间为3.5 h时,蒸谷米的品质最好,VB1含量最高。     

不同工艺条件对蒸谷米品质的影响

以早籼稻为原料,设定浸泡温度65、70、75℃,浸泡时间3、3.5、4h,蒸煮温度90、95、100℃,蒸煮时间25、30、35 min,进行L9(34)正交试验,分别测定各参数组合处理所得产品的色度、营养品质和蒸煮品质。综合各品质指标选出生产蒸谷米的最佳工艺条件为:浸泡条件为65℃~70℃、3.5 h~4 h,蒸煮条件为100℃、30 min。     

超声波辅助浸泡对稻谷含水量和蒸谷米品质的影响

以早籼稻为材料,研究超声波功率、超声波处理时间及料液比对稻谷含水量、蒸谷米的整精米率以及糊化特性的影响,并采用正交试验对超声波辅助浸泡工艺进行优化。结果表明:在超声波功率为600W,超声波处理时间为25min,料液比为1∶3(g/mL)时的工艺组合条件最优,整精米率达68.82%,蒸谷米的品质最好。     

不同贮藏条件对发芽蒸谷米品质的影响

为探究不同贮藏条件(包装材料、氧气含量和温度)对发芽蒸谷米的理化性质、生物活性物质、抗氧化活性、微生物学特性的影响,将发芽蒸谷米在真空和常压状态下分别包装在铝层压聚乙烯(aluminum-laminated-polyethylene,ALPE)和聚酰胺-聚乙烯(polyamide-polyethylene,PAPE)包...     

基于蒸谷米制备前后品质性状及糊化特性的评价分析

本试验选取12个不同品种的稻谷在相同工艺条件下制备蒸谷米,比较分析蒸谷米制备前后其品质性状及糊化特性的变化趋势.结果表明:'玉针香'、'天丰B'、'SN16-236'、'贵丰优785'、'两优68'和'徽两优1898'蒸谷米的碾磨品质相对均优于制备前,而'SN16-236'、'两优68'和'徽两优1898'蒸谷米的黄粒...     

蒸谷米加工工艺及品质的研究进展

蒸谷米是以稻谷或糙米原料,经过浸泡、蒸煮和干燥等一系列水热处理后,再经常规碾米工序得到的一类大米产品。蒸谷米在制备过程中发生水合-脱水、淀粉糊化和老化等系列理化变化,赋予其高营养、耐储存等特点,是一种营养健康的主食产品。该文综述蒸谷米加工过程及发生的理化变化,阐明加工和理化变化对蒸谷米产品品质的影响,以期为蒸谷米加工技术的改进以及产品品质的改善提供理论指导。     

基于主成分分析和聚类分析综合评价蒸谷米的品质特性

为探讨蒸谷米的品质并建立其评价体系,本试验选取12个不同品种的稻谷原料制备蒸谷米,并对其碾磨品质、外观品质、营养品质、食味品质和糊化特性的品质指标进行测定分析,考察不同品种稻谷制得的蒸谷米各项品质指标之间的差异性。同时,采用主成分分析法和聚类分析法对蒸谷米的品质进行综合性评价并建立蒸谷米品质评价模型。结果表明,不同品种稻谷制得的蒸谷米各项品质指标之间均存在差异性（P<0.05）,且品质指标间变异系数各不相同,说明蒸谷米在不同品质性状之间呈现不同程度的变化。由主成分分析发现23个反映不同品种稻谷制得的蒸谷米品质的指标可以用6个主成分表示,其累积方差贡献率为91.083%;根据聚类分析结果可知,爆腰率、黄米粒、外观、蛋白质、崩解值、峰值黏度、最终黏度和回生值8个品质指标可以用来综合评价蒸谷米品质的优劣。12个不同品种稻谷制得的蒸谷米中,“玉针香”的品质最佳,“大粒香”的品质最差,其次为“粤丰B”。主成分分析结合聚类分析综合评价方法可为不同品种稻谷制备蒸谷米的品质评价提供参考,并为蒸谷米专用稻的选育及蒸谷米资源的开发应用奠定理论依据。     

蒸谷米加工工艺及营养、储存特性探讨

结合实际介绍了蒸谷米的加工工艺;从营养、膳食、储存角度对蒸谷米与普通白米的营养及储存特性进行了分析,指出了蒸谷米在此方面具有的优势;对蒸谷米的发展前景进行了探讨.     

磨粉方式对苦荞粉粉质特性及体外消化特性的影响

选用超微、石磨、钢磨、湿磨4种磨粉方式对苦荞籽粒进行磨粉,分析比较苦荞粉破损淀粉含量、粒径分布、微观结构、水合特性、冻融稳定性、黏度特性等粉质特性并采用酶解法模拟体外淀粉消化测定不同时间点的总淀粉水解率。研究结果显示:磨粉方式对苦荞粉粉质特性及体外消化特性影响差异显著,其中超微粉碎能显著减小苦荞粉粒径大小(D[4,3]=32.09μm),提高其亮度值(L=88.92)以及淀粉对酶的敏感度;湿磨粉淀粉颗粒形态完整,破损淀粉质量分数最低,为4.25%,冻融稳定性好,回生值低(3 732 cP),不易老化;石磨粉粉糊衰减值低,粉糊热稳定性好,淀粉水解缓慢;刚磨粉对各项指标的影响均不突出。不同磨粉方式对苦荞粉的影响不一,超微粉是一种理想的苦荞深加工食品原料,湿磨粉则适合冷冻食品加工,石磨粉更适合慢消化食品加工,而刚磨粉适合与普通食品用粉。     

Effect of ascorbic acid and citric acid on the quality of salted Chinese cabbage during storage

Changes in color, browning indices, enzyme activity, and physical and chemical quality during the storage period were investigated to assess the effectiveness of storage period extension along with the addition of ascorbic acid (AA) and citric acid (CA) to salted Chinese cabbage. After 16 days of storage, the change in chromaticity value showed treatment with 0.5% CA showed the lowest change in the brown index during the storage period. The control showed the highest residual activity of polyphenol oxidase among control, AA, and CA-treated salted cabbage. AA and CA treatment effectively inhibited the initial populations of microorganisms including total aerobic bacteria, lactic acid bacteria, and yeast and molds in salted Chinese cabbage during storage. Further, the texture, i.e., hardness, chewability, and elasticity, tended to decrease with increasing storage. These results suggest that treatment with AA could help maintain the quality of salted Chinese cabbage during the storage period.     

Optimisation of in vitro measurement of available iron from different fortificants in citric fruit juices

The percentage of dialyzable ferrous and total iron were studied in a citric juice (pineapple and passion fruit) fortified with ferrous sulphate, micronised dispersible ferric pyrophosphate and ferrous bis-glycinate in similar concentrations (49.2 mg Fe/l). The in vitro method of Kapsokefalou and Miller (1991) [Kapsokefalou, M., & Miller, D. D. (1991). Effects of meat and selected food components on the valence of nonheme iron during in vitro digestion. Journal of Food Science, 56, 352–355.] was optimised for this matrix using 0.15 N PIPES buffer (pH 8.5) to adjust pH during pancreatic digestion. We also studied different pH values of Hepes buffer used in the measurement of iron concentrations with Ferrozine (chromogen solution). The maximum absorbances were obtained with a Hepes buffer pH value of 8.5. Ferrous sulphate was used as a reference salt due to its high bioavailability, although novel compounds, such as ferrous bis-glycinate and micronised dispersible ferric pyrophosphate, showed a high relative iron availability in this juice. Taking into account that percentage of dialysable ferrous iron is considered to be the more available fraction of total iron, the iron fortificant ferrous bis-glycinate proved to be more adequate for fortifing citric juices, giving a 10.7% of dialyzable ferrous iron. Moreover, the percentage of dialyzable total iron from ferrous bis-glycinate (31.0%) was statistically higher than those from ferrous sulphate and micronised ferric pyrophosphate (28.4% and 28.2%, respectively).     

Effect of citric acid deamidation on in vitro digestibility and antioxidant properties of wheat gluten

The effects of citric acid deamidation on the physiochemical properties of wheat gluten were investigated. In vitro digestion was carried out to determine changes of molecular weight distribution, amino acids composition and antioxidant efficacy of wheat gluten hydrolysates. Results indicated that citric acid deamidation significantly increased gluten solubility and surface hydrophobicity, at a neutral pH. Deamidation induced molecular weight distribution change of gluten with little proteolysis. Results from FTIR indicated that the α-helix and β-turn of deamidated gluten increased accompanied by a decrease of the β-sheet structure. After deamidation, in vitro pepsin digestibility of wheat gluten decreased, while in vitro pancreatin digestibility increased. The oxygen radical absorbance capacity (ORAC) activity of the in vitro digests decreased with increase of deamidation time. The high Lys and total essential AAs amounts in the final digests suggested that the nutritional values of wheat gluten after deamidation might be enhanced.     

湿热及酶解处理对糯米粉体外消化特性和血糖生成指数的影响

目的 研究酶解处理、湿热处理和湿热复合酶解处理对糯米粉体外消化特性和血糖生成指数(glycemic index, GI)的影响。方法 采用体外消化法测定了不同处理糯米粉的水解度和血糖生成指数值, 并通过X-射线衍射和激光共焦拉曼光谱实验测定了不同处理糯米的淀粉晶体结构。结果 3种处理的水解度和抗性淀粉(resistant starch, RS)相对含量增加, 慢消化淀粉(slowly digestible starch, SDS)相对含量降低; 其中湿热复合酶解处理条件下, RS相对含量最高, 为71.31%; 酶解处理条件下, RS相对含量最低, 为67.66%。酶解处理、湿热处理和湿热复合酶解处理的GI值分别为79.1、76.0和70.6。3种处理后糯米淀粉的晶体结构发生改变, 3种处理均使分子短程有序度与结晶度增加, 其中湿热复合酶解处理条件下, 结晶度最高, 为34.41%。 结论 湿热复合酶解处理后的糯米粉抗消化特性增强且GI值降低, 湿热复合酶解工艺可能通过影响糯米粉的体外消化率来降低GI值。     

水热处理对大米品质特性及其体外消化的研究

以籼稻为原料,采用超声波、蒸煮、超高压等一系列辅助处理,通过单因素和正交实验优化,得到慢消化蒸谷米的最优工艺参数为：超声波大小550 W、蒸煮时间30 min、超高压功率450 MPa,最终产品GI值为46,属于低GI食品。并通过GC-MS、电子鼻、傅里叶红外光谱对其消化特性和品质特性进行分析。结果表明,电子鼻主成分分析总贡献率高达97.9%,GC-MS实验中得出慢消化蒸谷米出现了反式-2-癸烯醛、2-丁基-2-辛烯醛、苯甲酸乙烯酯以及2-己基-1-癸醇等特征性香气成分,傅里叶红外光谱数据表明超高压、超声波等一系列处理促进了淀粉糊化。其模糊综合感官评分为86.3,由此可知慢消化蒸谷米品质较好,气味、外观品质、软硬度、弹性、黏性均具有良好的感官品质。     

Effects of ascorbic and citric acid on beef lumbar vertebrae marrow colour

Citric acid was evaluated as a way of improving ascorbic acid’s ability to stabilize beef lumbar vertebrae colour in high-oxygen packaging (MAP; 80% O₂/20% CO₂). Vertebrae were treated with citric acid (1%, 3%, or 10%), ascorbic acid (1%, 3%, or 10%), or a combination of both. Citric acid demonstrated no positive effects (P > 0.05), compared with ascorbic acid, which inhibited (P < 0.05) discolouration throughout the 7d display. Although ascorbic acid inhibited discolouration (visual colour and a^∗; P < 0.05), 3% and 10% ascorbic acid were most effective. However, if vertebrae are displayed for less than 7d, there may be no significant colour-stabilizing advantages associated with increasing ascorbic acid from 3 to 10%. The significant oxidizing effects of citric acid at 10% were reversed (P < 0.05) by ascorbic acid. Combining citric and ascorbic acid had no synergistic affect (P > 0.05) on vertebrae colour.     

柠檬酸在食品工业中的应用

柠檬酸以其独特的性质在食品加工业中广泛应用,是一种用量相当大的食品添加剂。文章概述了柠檬酸的性状及其在食品工业中的主要用途。     

乳酸处理对大米淀粉性质的影响

研究乳酸处理对大米淀粉性质的影响.结果表明,乳酸处理后大米淀粉中直链淀粉含量由17.86%增加到23.22%(第2天),到第7天降为18.13%;总淀粉含量从90.89%下降为82.02%;95℃时测定,溶解度从5.0%到第3天增加为14%,膨胀度从5.06降到4.72;透明度和凝沉率略有下降;通过物性测试仪,测定硬度由138.59 g降为70.81 g,弹性基本维持在0.99;通过黏度快速测定仪,乳酸处理后大米淀粉的糊化温度升高,第5天达到最高糊化温度86.7℃,峰值黏度下降,第7天达到最小值201.88 RVU,衰减值增加,热稳定性变差,回生值变化不大.     

不同链长单甘酯-籼米淀粉复合物结构及体外消化特性

研究不同链长脂肪酸单甘酯添加量变化时,单甘酯-籼米淀粉复合指数和糊化性质双变量相关性,通过傅里叶变换红外光谱仪、差示扫描量热仪、X-射线衍射分析仪和扫描电镜,研究单甘酯链长、添加量及温度对籼米淀粉-单甘酯复合物结构和体外消化特性的影响。研究结果表明:单甘酯碳链越长,与籼米淀粉的复合程度越高,且越易在冷却过程中形成黏度峰。相比于月桂酸单甘酯和硬脂酸单甘酯,棕榈酸单甘酯与籼米淀粉形成的复合物具有更高的焓变值、结晶度。硬脂酸单甘酯-籼米淀粉复合指数和糊化特性显著相关(除最低黏度值外);不同链长脂肪酸单甘酯-籼米淀粉复合指数与快消化淀粉含量显著负相关。