脂肪酸对稻米淀粉流变性的影响

为了解脂肪酸对稻米淀粉糊流变特性的影响,利用旋转黏度仪测定了月桂酸、豆蔻酸、棕榈酸和硬脂酸与稻米淀粉结合形成复合物后淀粉糊的流变特性。结果表明,分别将1.0%、2.0%和3.0%的脂肪酸添加到稻米淀粉中,在95℃下蒸煮5、10和15 min,复合指数随脂肪酸量的增加而增加,随碳链增加而降低;黏度系数随复合物的增加而增加,而流变指数则随复合物的增加而降低;在4种脂肪酸中月桂酸与淀粉形成复合物的能力最强,对稻米淀粉的流变性影响最显著。     

高压均质对板栗淀粉糊化、流变及质构特性的影响

研究了不同均质压力、均质次数、淀粉乳浓度对板栗淀粉糊化、流变、质构及偏光特性的影响。经20～100 MPa处理后,峰值、谷值和终值黏度较原淀粉减小2. 36%～8. 58%、4. 33%～12. 73%和2. 88%～8. 92%;增加均质次数,崩解值和糊化温度分别降低3. 03%～15. 54%和3. 90%～7. 42%;经高压均质处理后,质量分数为1%～10%淀粉乳的峰值、谷值和终值黏度下降4. 59%～8. 58%、11. 24%～12. 73%和7. 35%～8. 22%。同时,高压均质处理后淀粉糊稠度系数减小,储能模量和损耗模量显著降低,硬度、黏性、弹性等凝胶特性显著改变,且淀粉偏光十字模糊,结晶区被破坏。高压、少次、高浓度条件下的均质改性效果最佳,所得的淀粉黏度低、黏弹性减小、抗剪切稀化且凝胶强度低,可显著改善板栗乳饮料、板栗营养粉等产品的稳定性、口感与消化性。     

脂肪酸链长对高直链玉米淀粉—脂质复合物结构及理化性质的影响

目的：探究淀粉—脂质复合物的形成机理。方法：采用12~18个碳链的脂肪酸与脱支/非脱支高直链玉米淀粉复合,利用差示扫描量热仪、X-射线衍射仪、傅里叶红外光谱仪等分析复合物的热特性、结晶结构及有序结构等,探究脂肪酸链长及脱支/非脱支高直链玉米淀粉对淀粉—脂肪酸复合物结构及性质的影响。结果：脱支处理的淀粉与脂肪酸的复合率随碳链的增长而降低,其中月桂酸复合率最高(15.00%);未脱支处理的淀粉与脂肪酸的复合率随碳链的增长先升高后下降,其中软脂酸复合率(13.73%)最高。复合物的热特性、结晶结构、分子有序度等与其复合程度有关,淀粉和脂肪酸复合后,糊化峰值温度升高,热稳定性升高,经复合后,淀粉由B型结晶结构转变为V型。结论：脂肪酸链长及淀粉脱支对淀粉—脂质复合物结构及理化性质具有较大影响。     

蒸煮对不同品质鸭肥肝营养特性及脂肪酸组成的影响

研究3种不同品质的鸭肥肝在蒸煮后常规养分、脂肪酸组成及脂质过氧化的变化。结果表明:1)熟化增加了鸭肥肝中C12:0、总脂和丙二醛(MDA)的含量,降低了水分、蛋白的含量,对鸭肥肝中糖原的含量无影响;2)鱼油组肥肝熟化后,其SFA、PUFA、n-6PUFA、n-3PUFA、EPA、DHA均显著高于大豆油组肥肝(P<0.05),极显著高于玉米组肥肝(P<0.01);3)玉米组肥肝熟化后SFA和MUFA显著降低(P<0.05),PUFA、n-6 PUFA、n-3 PUFA显著升高(P<0.05),大豆油组肥肝熟化对这几种脂肪酸的影响不大,而鱼油组肥肝熟化后这几种脂肪酸含量均升高,其中n-6PUFA达到显著水平(P<0.05);4)熟化具有降低3种肥肝中EPA和DHA的趋势,EPA降低幅度以玉米组肥肝最大,DHA降低幅度以大豆油组肥肝最大。以上结果提示,鱼油组肥肝的食用价值最高。     

淀粉-脂肪酸复合物的研究进展

文章综述了淀粉-脂肪酸复合物的复合机理、制备方法及条件,重点讨论了影响淀粉-脂肪酸复合物形成的因素,发现淀粉结构、脂质结构、脂质浓度以及不同工艺参数对淀粉-脂肪酸复合物的影响很大,并以此为基础探究复合物对淀粉性质的影响,综述了淀粉-脂质复合物在淀粉基食品中的应用进展,以期为进一步推广和完善淀粉-脂质复合物在食品工业中的应用提供参考。     

湿热处理对板栗淀粉特性的影响

对板栗淀粉进行湿热处理,分析处理方法对淀粉颗粒结构、理化特性和体外消化性的影响。结果表明,湿热处理能改变板栗淀粉的理化特性和体外消化性。湿热处理使样品的直链淀粉含量降低,淀粉破损率增大,部分淀粉颗粒破碎,颗粒表面出现凹坑和孔洞。湿热处理对淀粉的晶体结构破坏较大,淀粉仍为C型晶体,结晶度降低,膨胀度降低。DSC分析表明,湿热处理后凝胶化温度(Tp和Tc)均有所升高,ΔH显著降低。湿热处理提高了板栗淀粉的SDS含量,降低了RDS和RS含量。     

低压处理对板栗淀粉理化特性的影响

以安徽大红袍板栗为原料,采用场扫描电镜和光学显微镜分析板栗淀粉在不同压力和料液比条件下表观形态和晶体特性的变化。结果表明:在相同的时间条件下,随着压力增大,板栗淀粉颗粒越易膨胀破裂,当压力为0.05MPa时,淀粉颗粒表面出现泡状凸起;随着淀粉体系中水分含量的升高,板栗淀粉颗粒越易膨胀破裂,料液比达到1∶1,压力为0.05MPa时,大部分淀粉颗粒破碎崩溃。溶解度试验中,不同压力、水分处理后,压力增大,板栗淀粉溶解度随之增大;压力一定,水分含量越高,溶解度越大。不同压力、水分处理后的板栗淀粉的晶体特性表明,压力不会改变板栗淀粉的晶体类型,但随着压力增大,淀粉中水分含量增大和处理时间延长,板栗淀粉晶体区面积缩小,晶体含量降低。     

锥栗直链淀粉-脂肪酸复合物的热特性

以自制锥栗直链淀粉为原料,利用DMSO水溶法分别在60℃和90℃的结晶温度下制备己酸、葵酸、硬脂酸的直链淀粉-脂肪酸复合物,并对其热特性进行了研究。结果表明:与锥栗直链淀粉相比,各种锥栗直链淀粉-脂肪酸复合物的糊化温度与糊化焓、热裂解温度与裂解焓均有不同程度的升高,而其回生焓与回生度、凝固点与玻璃化转变温度却变低,且前者随其复合率的增大而增高,而后者随其复合率的增高而降低。     

锥栗直链淀粉-脂肪酸复合物的结构特性

以自制锥栗直链淀粉为原料,利用DMSO水溶法在3种不同结晶温度下(30、60、90℃)制备己酸、葵酸、硬脂酸的直链淀粉-脂肪酸复合物,并对其结构特性进行了研究。试验结果表明:与锥栗直链淀粉比较,锥栗直链淀粉-脂肪酸复合物的吸水率、碘亲合力、蓝值、微晶比例与结晶度都下降;就己酸、葵酸、硬脂酸而言,较长的链长或较高的温度均有利于复合物的形成与稳定;锥栗直链淀粉-脂肪酸复合物属于典型的V型晶体,且它们的微晶比例、结晶度与脂肪酸性质有关,同一温度下制备的不同脂肪酸复合物,其微晶比例与结晶度均随脂肪酸碳链增长而降低;同种脂肪酸与锥栗直链淀粉形成的复合物,其微晶比例与结晶度则随复合物形成温度升高而降低。     

湿热-蒸煮处理对板栗淀粉-多酚复合物消化和回生性能的影响

该研究利用湿热-蒸煮处理制备板栗淀粉-多酚复合物,系统考察了在湿热-蒸煮处理条件下,多酚复合作用对板栗淀粉消化及回生性能的影响规律。结果显示,湿热处理可以显著提高板栗淀粉的抗消化性能,但会促进板栗淀粉的回生性能。而湿热-蒸煮处理过程中,多酚（绿原酸/咖啡酸）的添加能进一步提高淀粉的抗消化性能（抗消化成分含量：淀粉-绿原酸复合物6.77%;淀粉-咖啡酸复合物7.61%）;同时在回生过程中多酚可以有效抑制淀粉长程有序结晶和聚集态结构的形成,从而降低板栗淀粉的回生（抗回生率：淀粉-绿原酸复合物16.25%;淀粉-咖啡酸复合物22.99%）。其中相对于绿原酸,咖啡酸对板栗淀粉的抗消化性能及抑制其回生的效果更为显著。此外,相对于高水分含量（90%）体系,60%水分含量蒸煮处理后的所有板栗淀粉-多酚复合物的抗消化性能和抗回生程度均更高。研究结果将为获得更长货架期的新型高品质板栗淀粉基营养健康食品提供基础数据及理论支撑。     

Effects of chestnut tannins on carcass characteristics, meat quality, lipid oxidation and fatty acid composition of rabbits

Seventy two male Bianca Italiana rabbits were used to study the effects of the inclusion (0%, 0.5%, and 1.0%) of a natural extract of chestnut wood (Silvafeed ENC) in the diet on productive traits, carcass characteristics, meat quality, lipid oxidation and fatty acid composition of rabbit meat. Results showed ENC had no significant effect on live weight, productive traits, hot carcass weight, dressing percentage, skin weight, pH, cooking losses, shear force and colour. The iron content was higher in Longissimus thoracis et lumborum (LTL) muscle of rabbit fed the ENC 1.0% diet than the control group. TBARS average values in the group ENC 0.5% were significantly lower (P < 0.05) than in the control and ENC 1.0% groups. Myristic acid (C14:0; P < 0.01), palmitoleic acid (C16:1 cis-9; P < 0.05) and pentadecanoic acid (C15:0; P < 0.01) contents were lower in LTL muscle of rabbits fed the ENC 1.0% diet, whereas the palmitic acid (C16:0) content was higher (P < 0.05) in the rabbits of this group. Moreover, the rabbits fed with the ENC 0.5% diet had lower (P < 0.01) levels of trans-vaccenic acid (C18:1 trans-11) compared to rabbits fed with the control diet. No significant differences were observed in saturated (SFA), monounsaturated (MUFA), polyunsaturated (PUFA) fatty acids, as well as in PUFA/SFA and n − 6/n − 3 ratios among the groups.     

Phase transitions in starch based films containing fatty acids. Effect on water sorption and mechanical behaviour

The water sorption capacity (WSC) of starch films containing, or not, glycerol (1:0.25 starch:glycerol ratio) and fatty (palmitic, stearic and oleic) acids (1:0.15 starch:fatty acid ratio) was analysed at 10, 25 and 40 °C in the entire range of a_w. Starch re-crystallization during the equilibration time was also analysed by X-ray diffraction. Likewise, the glass transition and lipid melting properties as a function of the film water activity were determined. Mechanical behaviour was also analysed at 25 °C for film samples equilibrated at 0, 53, 68 and 75% RH. Crystallization was promoted at low temperature and high relative humidity which modifies the expected tendencies in WSC as a function of the temperature. In relationship with this, V-type structures were formed during time, mainly in fatty acids containing films. Glass transition of the starch matrix at low moisture contents was affected by the presence of saturated fatty acids. Microstructural observations seem to corroborate the complex formation between these and the polymer chains. The mechanical behaviour of the films, as a function of the moisture content, is coherent with the results of the phase transition analysis and microstructural observations. The plasticization effects and the structural discontinuities in the polymer matrices determine the value of the elastic modulus and the behaviour at break.     

Effects of cooking and reheating methods on the fatty acid profile of sea bream treated with rosemary extract

BACKGROUND: The effects of rosemary extract on the fatty acid profile of sea bream fillets cooked by different methods (oven baking, grilling and pan frying) as well as the effects of different reheating methods (microwave and conventional oven) on the fatty acid composition of fish after frozen storage for 4 months were investigated. RESULTS: The proportion of saturated fatty acids increased only slightly in fried samples but significantly in oven‐baked and grilled samples, while the proportion of polyunsaturated fatty acids (PUFAs) increased significantly in fried samples but only slightly in oven‐baked and grilled samples. The proportion of monounsaturated fatty acids remained relatively constant after cooking. Of the fatty acids analysed, the most significant increases (P < 0.05) were observed in C18:1n‐9 and C18:2n‐6 and the most significant decreases (P < 0.05) in C14:0, C16:1, C20:5n‐3 and C22:6n‐3. Although sea bream fillets fried in sunflower oil showed an increase in PUFAs, the lowest eicosapentaenoic and docosahexaenoic acid contents were found in fried samples. CONCLUSION: Sea bream fillets treated with rosemary extract showed slower oxidation than untreated fish. Neither conventional nor microwave reheating after frozen storage for 4 months had a detrimental effect on the fatty acid profile and its stability. Copyright © 2009 Society of Chemical Industry     

不同蒸煮方式对藜麦营养特性及风味的影响

研究常压蒸煮、高压蒸煮、微波蒸煮三种不同蒸煮方式对藜麦的营养特性(VB1、VB2的损失;酚类物质含量和组成;淀粉水解率)的影响,并采用固相微萃取联用气相色谱-质谱技术对样品的风味物质进行分析。结果表明:与其他两种蒸煮方式相比,常压蒸煮藜麦可保留较多的VB1、VB2,有较低的淀粉水解指数,可产生更多的风味物质。但在酚类物质的保留上,常压蒸煮不及高压蒸煮。因此,常压蒸煮可能是一种较适于藜麦的烹调方式。     

Rheological properties of a soluble self-assembled complex from starch, protein and free fatty acids

Controlled interaction among amylose, protein and free fatty acids was performed using a pasting cell installed in a rheometer resulting in the formation of a soluble high molecular weight complex. Rheological characterization of solutions of the formed complex as well as during its formation in a range of temperatures of 25-95 °C and shear conditions ranging from 2.5 to 16.7 rad/s were performed. Different fatty acids (oleic acid, linoleic, palmitic, and conjugated linoleic acids), corn starch and whey protein, in a range of protein concentrations from 3.75% to 10% were used to produce the complex. By using rheological techniques and size exclusion chromatography was found that concentration of protein, type of free fatty acid, temperature, time and shear rates, all, had a significant effect on the formation of the complex and its rheological properties. Rheological results proved that the formation of the complex starts at 75 °C but its structure set during cooling at 55 °C. Increases in the shear rates applied during the complex formation significantly reduced its viscosity. Increases in the amount of protein increased the order of the complex. Conjugated linoleic acid, a bioactive compound, was able to be incorporated in the complex but using a slower heating rate than that used for the other fatty acids.     

不同干燥方式对重组营养强化米品质调控效应

在明确重组营养强化米自然风干、热风干燥、微波干燥、电热真空干燥及冷冻干燥5种干燥工艺最佳参数基础上,分析不同干燥工艺对重组营养强化米品质调控效应。结果表明,电热真空干燥最佳工艺条件真空度0.025MPa、干燥温度为35℃、干燥时间2.5h条件下的重组米米粒横截面致密性、适口性、冷饭质地及感官评价总分最优,且综合蒸煮品质及质构特性最佳,其中,加热吸水率280.45%、膨胀率268.57%,米汤可溶性固形物重量56.657mg/g,米粒弹性0.873mm、粘聚性0.549gs、回复性值0.192gs;而微波功率210W,干燥时间50min的微波干燥米粒蒸煮后外观结构最佳,硬度3650.873g最小;温度-90℃,干燥时间24h的冷冻干燥工艺下米粒胶着度2788.654g、咀嚼度1819.708g最大。综合分析干燥工艺对强化米品质调控效应表明,电热真空干燥适于重组营养强化米品质的保持。      

The effects of industrial pre-frying and domestic cooking methods on the nutritional compositions and fatty acid profiles of two different frozen breaded foods

This study was carried out to determine the effects of manufacturer pre-frying in olive and sunflower oil, as well as domestic cooking methods (deep-frying in olive and sunflower oil and baking) on the proximate compositions and fatty acid profiles of tuna pasties and ham nuggets. The pre-frying processes reduced moisture and carbohydrates and increased ash, fat and protein content in both pre-fried products. During cooking, the frying processes caused a reduction in moisture content and an increase in fat content in relation to pre-fried samples, while baking did not modify the proximate composition. The fatty acid profiles of products during both the pre-frying and frying processes became similar to those of the culinary fat used. Thus, the frying processes reduced the proportion of saturated fatty acids (SFA) and increased the proportion of monounsaturated fatty acids (MUFA) in the foods when olive oil was used, whereas increased the proportion of polyunsaturated fatty acids (PUFA) in products fried in sunflower oil. The fatty acid profiles of fried samples tended to be more similar to the frying fat than to the pre-frying fat, whereas the fatty acid profiles identified during the pre-frying process for baked products were not significantly modified. Thus, samples pre-fried in olive oil and subsequently baked showed the best proportion of fat content and PUFA/SFA, MUFA + PUFA/SFA and n-6/n-3 ratios of the tested products.     

Effects of different cooking methods on some chemical and sensory properties of Galega kale

Kale (Brassica oleracea L. var. acephala) is rich in bioactive phytochemicals such as phenolic compounds and vitamins. However, cooking the plants can cause important changes in composition. The objective of this study was to investigate the effect of some domestic cooking processes (boiling, steaming, microwaving and pressure cooking) on several quality parameters of Galega kale. Boiling had the strongest effect on the antioxidant capacity (the IC₅₀ was four times higher than in the fresh sample), total phenolics (losses of 76.4–77.9%) and colour (ΔE = 17.79–19.12). Microwaving caused the greatest loss of soluble solids (80.8–82.2%). Steaming seems to be the best method for retaining the nutrient and antioxidant capacity of kale (100% ash, 71–77.5% soluble solids, 100% antioxidant capacity, 67–71% total phenolics, 62–71% chlorophyll). However, steamed kale was awarded the lowest sensory scores, indicating the difficulty in reconciling nutritional value and sensorial quality. Use of discriminant statistical techniques enabled the classification of 100% of samples.     

Effects of cooking methods on starch hydrolysis kinetics and digestion-resistant fractions of rice and soybean

In this study, we investigated the effects of cooking methods and digestion-resistant fractions on the starch hydrolysis kinetics of rice and soybeans. The RS1 contents in unheated rice and soybeans were found to be high at 5.3 and 4.9%, respectively. After heating, the RS1 levels of the rice and soybeans were significantly reduced to 0.4 and 2.4%, respectively. The total nonstarch polysaccharide (NSP) content was not significantly different according to heat treatment, but the heat treatments affected the amounts of water insoluble nonstarch polysaccharides (WISNSP) and water soluble nonstarch polysaccharides (WSNSP). The level of WISNSP in the unheated samples was higher than the WSNSP of both samples; however, the WISNSP level showed a reducing trend after heating. Also, total pentosan and water soluble pentosan contents showed similar trends with total NSP and WSNSP. The hydrolysis indices (HI) of the unheated rice and soybeans were low (36.2 and 40.3%), while the heated group had high levels (89.5 and 45.0%). Among the cooking methods, the highest kinetic constants (0.284 and 0.199) were found with autoclaving for both rice and soybeans, followed by electric cooker (0.282 and 0.170), microwave oven (0.256 and 0.155), and stone pot (0.238 and 0.167). Particularly, all soybean samples appeared to have lower starch hydrolysis kinetics than the rice samples. The RS contents of the rice and soybeans were highest in the samples that were cooked in the stone pot, at 1.2 and 3.8%, respectively.