Rheological,textural, micro-structural and sensory properties of mango jam

Mango jam behaved as pseudoplastic fluid exhibiting yield stress. The Herschel–Bulkley (HB) model described adequately the steady-state rheological behavior of jam. Temperature dependence of the consistency index followed Arrhenius relationship. Time dependent structural breakdown characteristics of mango jam followed Hahn model. Hardness of mango jam increased with pectin concentration and acidity. Hardness increased up to 60% sugar concentration but decreased with further increase in sugar concentration at all pH and pectin levels. Stickiness, work of shear, and adhesion did not show any systematic trend with pH, pectin, and sugar concentration. The overall acceptability was rated highest for mango jam prepared with 65% sugar, 1% pectin at pH 3.4. Principal component analysis (PCA) revealed that hardness and work of shear are the most relevant among all the characteristics (physicochemical, sensory, textural, rheological, and compositional) studied for mango jam. Microstructure of mango jam was found to be composed of network regions with large pores as well as dense, compact regions with small pores.     

Physico-Chemical,antioxidant activities,textural, and sensory properties of yoghurt fortified with different states and rates of pomegranate seeds (Punica granatum L.)

This study examines the effects of incorporating fresh, frozen, osmodehydrated, and dried pomegranate seeds, at different concentrations (5, 10, and 20%) on the physicochemical, antioxidant, textural, and sensory properties of yoghurt. Antioxidant activity, pH, acidity, syneresis, and color of yoghurt were also evaluated during the storage (28 days) at 4°C. The principal component analysis (PCA) was performed to assess the correlations between different yoghurt formulation and their sensory attributes. Data showed that the addition of pomegranate seeds reduced pH and modified the chromatics coordinate (L*, a*, b*, C*, h°) and firmness of the yoghurt samples. In addition, acidity, °Brix, and syneresis increased compared to the control. Thanks to their high anthocyanin content, pomegranate seeds considerably improved the antioxidant activity essentially for yoghurt enriched with frozen seeds. In addition, the supplementation of 20% of frozen seeds into yoghurt was the most appreciated by panelists and improved the sensory properties in comparison to other formulation. According to PCA, taste and appearance were the main criteria for the overall acceptability of yoghurt. After 28 days of storage, the reddish color was reinforced; however, the antioxidant activity of yoghurts was reduced. Overall, it can be concluded that pomegranate seeds can be used as a natural ingredient to develop a novel yoghurt with high nutritional properties.     

影响米饭质构特性和感官的关键理化因素分析

选取来自统一产区的24个水稻品种,测定了稻米以及其所加工成米饭的理化特性,分析了稻米理化特性与米饭质构特性间的相关性,建立了质构特性及感官与理化因子间的回归方程,进一步分析影响米饭食味品质的一些关键因素。结果表明,淀粉与多个质构参数呈显著（p<0.05）或极显著（p<0.01）正相关关系;蛋白质与各质构参数相关性不大;水分与米饭的弹性显著相关（r=0.448,p<0.05）;游离氨基酸与粘连性极显著负相关（r=-0.576,p<0.01）,与弹性负相关（r=-0.423,p>0.05）;脂肪与硬度显著负相关（r=-0.420,p<0.05）,与其他质构参数也基本呈负相关;长宽比主要与反映淀粉特性的质构参数显著相关。回归分析表明,脂肪和游离氨基酸含量对米饭食用品质影响较大,当这两者含量低时,米饭质构特性更优良,而当游离氨基酸含量高时,米饭适口性好、感官评分值高。      

Sous vide pretreatment in cooking sturgeon fish burger: Effects on physicochemical properties and sensory characteristics

The effect of sous vide (SV) pretreatment on the physicochemical (texture, water holding capacity (WHC) and protein modifications) and sensory (appearance, odour, flavour and overall acceptability) properties of sturgeon fish burgers cooked by four common methods (steaming, baking, microwaving and frying) were investigated. The texture analysis results showed that SV combined with transglutaminase could make the structure of cooked fish burgers denser and increase the springiness (ranging from 3.60 to 4.97 mm) and chewiness (ranging from 4.50 to 9.57 N), especially in microwave-cooked samples. In terms of sensory quality, on the one hand, SV could effectively inhibit off-flavours from oxidation and prevents evaporative losses of flavour volatiles (nitrogen oxides, organic sulphur and aromatic compounds) during cooking. On the other hand, the overall acceptability of microwave-cooked sample pretreated with SV was higher than that of other cooking methods, especially compared with steaming (P < 0.05). The above results indicate that it is feasible to obtain common cooked fish burgers with improved physicochemical and good sensory properties using SV pretreatment.     

低温热处理对牦牛肉理化性质及感官特性的影响

该文探究低温条件下不同温度(55、65、75、85℃)和时间(20、30、40 min)的热处理对牦牛肉理化性质和感官特性的影响.结果表明,随加热温度升高和加热时间延长,蒸煮损失增大(P<0.05),水分含量减小(P<0.05),pH值增大(P>0.05),扫描电子显微镜观察发现肌纤维显著收缩.质构分析可知,牦牛肉的硬...     

4种特色红茶菌发酵液感官品质、理化特性及菌群结构比较研究

目的 揭示不同红茶菌发酵液品质差异的内在原因.方法 以4种特色的红茶菌发酵液为研究对象(标记为A、B、C、D),比较分析其在感官品质、理化特性和群落结构的差异.结果 4种红茶菌发酵液的香味、滋味差异较大,色泽差异较小,其中B在发酵第2 d具有独特发酵风味与茶香,色泽橙黄,口感清爽,综合评分最高,为74.2分;4种红茶菌...     

藜麦淀粉理化特性研究

藜麦(Chenopodium quinoa Willd.)是一种拟谷物,含有丰富的营养物质并具有药用和保健价值。本文采用X射线衍射(XRD)、扫描电子显微镜(SEM)和差示扫描量热仪(DSC)等对碱法和酶法提取的藜麦淀粉的结构和热性能进行了分析,并测定了藜麦淀粉的膨胀度、冻融稳定性和碘蓝值。结果表明,藜麦淀粉颗粒较小,平均粒径为1.15~1.97μm,支链淀粉含量较高。几种淀粉的溶解度、膨胀度、冻融稳定性、透光度和糊化温度等理化特性均与各自的结构特征相关,表现出不同程度的差异。      

4种高粱淀粉理化性质的比较分析

为充分利用不同品种高粱淀粉,对龙米粮1号、龙杂13号、红糯1号和红糯5号高粱淀粉的理化性质进行比较分析。结果表明,4种高粱淀粉颗粒均为不规则多角形,其中龙米粮1号的淀粉颗粒比表面积(S_w)最高为0.192 m²/g;经X衍射测得,4种淀粉均属于A型晶体,其中红糯5号相对结晶度较高为28.64%;傅里叶红外光谱结果表明,龙米粮1号有序程度较高为1.221;龙米粮1号的持水力和溶解度均最高为220.56%和39.07%,红糯1号的支链淀粉、透明度和析水率较高,分别为86.72%、39.23%和0.89%,龙杂13号的直链淀粉含量和凝沉性较好,而红糯5号的膨胀度较其他3个品种高;经糊化和热特性测定表明,龙米粮1号具有较高的成糊温度和峰值黏度,龙杂13号的热稳定性较好,红糯5号谷值黏度较高,红糯1号回生值较低,且2种红高粱淀粉较另2种白高粱的热焓值、起始、峰值、谷值、最终温度均较低。龙米粮1号可用于食品中的保水剂的应用,龙杂13号适用于食品中增稠剂的生产,红糯1号宜用来冷冻类食品的加工,红糯5号则适用于焙烤类食品的加工生产。     

Physicochemical,morphological, thermal,pasting, and textural properties of starch acetates

Acetylated starches are a commercially important group of modified starch known for their reduced retrogradation tendency, high clarity, low viscosity, high swelling power, and lower gelatinization temperature and time. Due to these remarkable properties, acetylation is a commonly used chemical modification for preparing stabilized starches. This review summarizes the methods used for preparation of starch acetates and corresponding effects of acetylation on morphological, thermal, pasting, digestibility, textural, and other functional characteristics of starches isolated from various botanical sources. Starch acetates are also useful as packaging material, as wall material for encapsulating active ingredients, and to improve the storage stability of different products.     

Influence of four different coagulants on the physicochemical properties,textural characteristics and flavour of tofu

The coagulation mechanism and quality characteristics of tofu depend on the choice of coagulant. The effects of using magnesium chloride (MgCl₂), calcium sulphate (CaSO₄), glucono-δ-lactone (GDL) and fermented soybean whey (FSW) as coagulants for tofu were investigated using solid-phase microextraction (SPME), two-dimensional gas chromatography coupled with mass spectrometry (GC×GC-MS), scanning electron microscopy (SEM) and analysis of textural characteristics and physicochemical properties. Results showed that GDL tofu exhibited the highest yield (202 g 100 g⁻¹) and moisture content (76.3%). FSW tofu had the highest protein content (18.5%), amino acid content (15.85%) and textural properties. GC×GC-MS analysis revealed the number of 49, 44, 55 and 63 flavour substances, respectively. In sensory evaluation tests, GDL tofu was reported to possess a smooth surface and white colour. The microstructure of FSW tofu was dense and uniform. Through the above technical researches, the study suggested FSW gave tofu the best quality, more unique flavour and more potential popular among consumers.     

荔枝核淀粉理化特性的研究

利用SEM、X-光射线衍射、Brabender黏度仪、DSC等研究荔枝核淀粉的理化性质。结果表明:荔枝核淀粉颗粒多呈椭圆形或多角形,平均粒径为12.6μm;有明显的黑十字且交叉点在颗粒中心;颗粒晶体结构为C型;起糊温度较高,为85.3℃,热稳定好,有黏度峰值,为177BU;DSC测得T°、Tp、Tc分别为69.04℃、78.79℃、87.08℃,ΔHgel为7.50J/g;支链淀粉、直链淀粉含量分别为88.8%和11.2%。     

大米淀粉结构与特性研究进展

大米淀粉是主要的谷物淀粉之一,具有一些独特的结构及物化特征。本文主要从淀粉颗粒结构、生长环结构、Blocklets小体、层状结构、结晶结构及链结构等多尺度结构层次和凝胶化、糊化、回生及消化等特性方面,对大米淀粉结构和物化特性进行了全面的综述,并阐述了大米淀粉不同层级结构对其特性的影响,同时介绍了大米淀粉的主要制备方法与组成成分及其对大米淀粉特性的影响,以期为大米淀粉的研究与开发提供借鉴。     

豌豆淀粉与马铃薯淀粉、玉米淀粉理化性质比较

通过对豌豆淀粉、马铃薯淀粉和玉米淀粉的基本组成、颗粒形态、凝沉性、糊化特性、透明度及抗性淀粉含量的测定与比较表明:豌豆淀粉中直链淀粉和蛋白质的含量较高,但其颗粒直径小于马铃薯淀粉;与马铃薯淀粉和玉米淀粉相比,豌豆淀粉易于回生,但糊稳定性较好;豌豆淀粉糊的透明度低于马铃薯淀粉,但其淀粉组成中慢消化淀粉含量高于马铃薯淀粉和玉米淀粉。      

不同修饰程度对蜡质玉米淀粉理化性质和消化特性的影响

利用淀粉蔗糖酶(AS)的转糖基活力修饰蜡质玉米淀粉(WCS),探索不同修饰程度对其理化性质和消化特性的影响。结果表明:在给定的反应条件下,酶反应进程可用对数函数进行模拟;与A型的原淀粉相比,改性WCS的结构更为致密,且呈现出B型结晶特性;改性前后淀粉的支链长度分布变化显著,随着转糖基率(TR)的增加,Fr I(聚合度(DP)30)组分所占比例显著增加,Fr III(DP13)组分所占比例显著减小;与原淀粉(抗性淀粉(RS)含量=0.8%)相比,改性WCS的RS含量明显提高(53.1%≤RS含量≤73.6%),随着TR的增加,改性WCS的RS含量呈现先增加后缓慢降低的趋势,在TR=88%时,RS含量达到最高(73.6%)。     

冻藏对小麦淀粉理化性质及热力学特性的影响

研究了冻藏对小麦淀粉颗粒表面形态、理化性质、热力学性质及凝沉特性的影响。通过扫描电镜(SEM)检测冻藏小麦淀粉颗粒,发现部分淀粉颗粒表面有破损;对冻藏后的小麦淀粉溶解度、粘度、膨润力、蓝值等进行测定,结果显示冻藏后淀粉溶解度和粘度分别增大了48.6%、43.2%;膨润力、蓝值分别降低8.41%、28.5%;采用示差量热扫描(DSC)测定冻藏小麦淀粉热力学性质变化,发现冻藏小麦淀粉糊化热焓降低了47.3%,糊化温度起止范围降低了10.60%;凝沉值降低了47.2%。研究表明冻藏后的小麦淀粉颗粒形态,理化性质、热力学性质均发生了明显改变。      

Comparison of optical and physical measurements with sensory assessment of the ripeness of tomato fruit Lycopersicon esculentum

Knowledge of the inter-relationships among objective physical and optical measurements and their relation with sensory perception of foods can be applied to improve quality control and consumer acceptance. Changes in the optical and mechanical properties of tomatoes were found to be related to the perceived ripeness of the fruit over a storage period. The sensory attributes and instrumental parameters significant in the assessment of ripening tomatoes were translucency, green, orange, lightness, hue and chroma. The chromatic co-ordinate a^* was significantly correlated with the mechanical modulus of the fruit, which in turn was inversely related to ripening associated with colour changes from green to red. It is feasible that mechanical and optical data may be combined to provide an on-line system for the evaluation of ripeness of tomato fruit.     

亲水胶体对淀粉理化性质影响的研究进展

本文综述了亲水胶体对淀粉糊化性质、流变性质、凝胶特性、老化性质、热力学性质、成膜性质及膨胀能力的影响,探讨了亲水胶体影响淀粉理化性质的作用机制,进一步介绍了淀粉-亲水胶体混合体系的应用,以便为合理地选择和使用亲水胶体提供理论依据。      

疣柄魔芋淀粉理化及功能性质研究

为了探索一种新的淀粉资源,对疣柄魔芋淀粉的性质进行了研究。通过电子显微镜、激光粒度分析、X-衍射分析、红外光谱分析等分析手段,并以玉米淀粉和木薯淀粉进为比较,结果显示:疣柄魔芋淀粉淀粉颗粒呈多面体形,棱角较尖锐突出;其粒径小于木薯淀粉和玉米淀粉;结晶型为A-型,相对结晶度为37.4%;红外光谱吸收峰、吸收强度与木薯淀粉和玉米淀粉基本相同;凝胶强度、糊化起始温度和糊化热焓高于木薯淀粉和玉米淀粉;且其抗酶解性优于木薯淀粉和玉米淀粉。因此,疣柄魔芋淀粉是一种潜在的可被开发为抗性淀粉的新资源淀粉。     

Effect of inulin on the textural and sensory properties of mortadella, a Spanish cooked meat product

Inulin is a fructooligosaccharide with demonstrable beneficial effects on health. Its effect on the textural and sensory properties of mortadella, a Spanish cooked meat product, was studied. Conventional (23% fat) and reduced‐fat sausages (10% fat) were prepared. Fat reduction yields an energy value reduction close to 33%. In both cases, inulin was incorporated, in powder and as gel form, in sufficient amounts to constitute the 2.5%, 5% and 7.5% of the final product. To evaluate the effect of inulin, instrumental measures of texture and sensory analysis (hedonic test) were performed. Textural analysis indicated that powdered inulin increases hardness and this fact was more evident in reduced‐fat sausages which showed that this changes even at concentrations of 2.5%. However, when inulin was incorporated as a gel, textural parameter changed only when the high levels were assayed (7.5%) showing softer sausages independent of the fat content. Sensory analysis was highly favourable and the overall acceptability was good in all batches in spite of the changes observed in texture. It can be established that this product can be enriched with inulin to a maximum level of 7.5% and preferably as gel with a good sensory quality.