Comparative Studies on Physico-Chemical Properties of Starches from Jackfruit Seed and Mung Bean

The physico-chemical properties of starch from jackfruit seed and mung bean were investigated. Jackfruit seed starch had much higher resistant starch content (26.99%) than that of mung bean starch (4.04%). Furthermore, jackfruit seed starch had a higher gelatinization temperature (T_o) that required more gelatinization energy (ΔH) compared to mung bean starch. However, mung bean starch had higher amylose content and its granules were much larger than that of jackfruit seed starch. Mung bean starch had the highest peak viscosity, breakdown, and setback whereas jackfruit seed starch had the highest pasting temperature. Amylopectin chain length of mung bean starch contained higher proportion of short chains (degrees of polymerization 6–12) but lower proportion of very long chains (degrees of polymerization > 37 ) comparing with jackfruit seed starch. The X-ray diffraction patterns showed both starches to be Type-A crystallinity. In addition, both starch gels showed higher the storage modulus (G′) than the loss modulus (G?) designating as rubber like material. However, mung bean starch gel exhibited higher G’ and less tan δ than that of jackfruit seed starch indicating much stronger of gel structure.     

油脂氧化稳定性的研究

用Ｒａｎｃｉｍａｔ仪器测定了油脂氧化稳定性。结果表明,温度的高低,脂肪酸不饱和度,抗氧化剂和增效剂的使用,均与油脂氧化稳定性有着密切的关系。     

鹰嘴豆、饭豆、绿豆淀粉性质的比较

以鹰嘴豆、饭豆、绿豆淀粉为对象,研究了不同豆类淀粉的糊化性、膨胀度、溶解度、淀粉-碘复合物的可见光谱、淀粉糊的透明度、冻融稳定性、凝沉性以及沉降体积等性质。结果表明:绿豆淀粉的成糊温度和峰黏度最高,而鹰嘴豆淀粉的热糊稳定性和冷糊稳定性最好;3种淀粉的膨胀度和溶解度均随温度的升高而增加,并且淀粉碘复合物可见光光谱的最大吸收波长都在620 nm左右。绿豆淀粉糊的透明度、冻融稳定性和凝沉性最好,沉降体积最大。     

Emulsion and Pasting Properties of Resistant Starch with Locust Bean Gum and their Utilization in Low Fat Cookie Formulations

In this study, emulsion and pasting properties of resistant starch (RS) preparations with/without locust bean gum and their utilization in low fat cookies were investigated. The acid-hydrolysed corn starch sample was autoclaved, stored at 95° C for 0, 2, 3, and 4 days for formation of RS preparations I, II, III, and IV, respectively. RS preparations had significantly lower peak and breakdown and higher trough viscosities than hydrolysed starch. RS preparations with gum resulted in a cold thickening capacity. While native and hydrolysed starches had deteriorative effect on emulsion capacity and stability of the soy protein, RS preparations (with/without gum) did not have a deteriorative effect. Reduction of shortening caused significant decrease in spread ratios of control cookies with/without gum. However, utilization of RS preparations in low fat cookies caused significant increases.     

Physicochemical,Rheological, and Thermal Properties of Six Types of Honey from Various Floral Origins in Tunisia

The present study was undertaken to determine the physicochemical, rheological, and thermal properties of six types of Tunisian honey samples from various floral origins (eucalyptus, orange, thyme, mint, rosemary, and horehound). All the honey samples exhibited non-Newtonian behavior at a shear rate ranging between 0.01 and 500 s^–1, with the highest levels of viscosity (µ) being observed for thyme, followed by eucalyptus, rosemary, mint, orange, and horehound honeys, respectively. The effect of temperature on the dynamic viscosity of the samples followed an Arrhenius-like pattern, with activation energy values ranging from 21.23 to 34.91 kJ/mol. The results from oscillatory rheology analysis also revealed that the loss modulus predominated over the storage one in the whole frequency range. As determined by differential scanning calorimetry, the glass transition (T_g) and melting temperatures of the Tunisian honey samples varied between –41.55 and –47.06 °C and between 197.9 and 221.1°C depending on their sugar compositions, respectively.     

氧化豆油活性基团的鞣性研究

在传统制革法中,油鞣是一种特殊鞣革的方式,非常强调天然不饱和油脂的作用。利用半干性油-豆油(具有较高的碘值125~135gI2/100g)进行油鞣,考察了pH、温度、时间、豆油用量和过氧化值(PV)对油鞣革收缩温度(Ts)的影响,试验结果表明:豆油没有体现出鞣性;收缩温度与过氧化值的高低没有直接关系。     

直链淀粉、蛋白质及脂类对大米粉热特性的影响

利用差示扫描量热仪(DSC)分别对籼米、粳米、泰国香米及糯米米粉热特性作了研究。实验结果表明:直链淀粉、蛋白质及脂类对米粉糊化熔点、峰值、糊化终点温度及糊化焓变有重要影响。直链淀粉显著影响大米米粉的糊化熔点、峰值和终点温度,高直链淀粉含量的大米米粉的糊化熔点、峰值和终点温度均高于中、低及糯米米粉;高直链淀粉含量的大米蒸煮性差、能耗高、蒸煮时间长,中、低直链淀粉含量的大米蒸煮性好、能耗少、蒸煮时间短。米粉中的蛋白质可能起到升高米粉糊化熔点、峰值及终点温度的作用;大米蛋白质含量越高,大米蒸煮性越差、能耗越高、蒸煮时间越长。米粉中的脂类对米粉热特性的影响较复杂,脂类可能起到降低糊化熔点糊化焓变的效果;大米中脂类含量越高,大米蒸煮性好、能耗少、蒸煮时间短。     

颗粒态绿豆抗性淀粉的制备及性质研究

以绿豆淀粉为原料,采用湿热处理制备颗粒态抗性淀粉,并研究其颗粒形貌、直链淀粉含量、溶胀度、黏度及结晶性质等。试验表明:淀粉经过湿热处理后,抗性淀粉含量显著提高;湿热处理淀粉仍保持完整的颗粒外观,属于颗粒态抗性淀粉,部分淀粉颗粒表面出现了裂纹和凹坑,偏光十字强度有所减弱;湿热处理淀粉的直链淀粉含量明显增加,而溶解度、膨胀度和峰值黏度下降,淀粉糊化变得困难;X-射线衍射图谱表明原淀粉和湿热处理淀粉都为"A"型结晶,且湿热处理淀粉在15.2°、17.4°、22.9°左右的衍射峰强度有所加强。     

Effect of oil content and processing conditions on the thermal behaviour and physicochemical stability of oil-in-water emulsions

The destabilisation mechanism of oil-in-water (o/w) emulsions was studied as a function of oil content (20% and 40% o/w), homogenisation conditions and crystallisation temperatures (10, 5, 0, −5 and −10 °C). A mixture of anhydrous milk fat and soya bean oil was used as the lipid phase and whey protein isolate (2 wt%) as emulsifier. Crystallisation and melting behaviours were analysed using differential scanning calorimetry. Physicochemical stability was measured with a vertical scan macroscopic analyser. Emulsions with 20% oil were found to be less stable than those with 40% oil. For 20% o/w emulsions, the crystallisation was delayed and inhibited in emulsions with smaller droplets and promoted in emulsions with larger droplets when compared with 40% o/w emulsions. Depending on the droplet sizes in the emulsion, the formation of lipid crystals (in combination with the emulsifier) either stabilises (small droplets) or destabilises (big droplets) the emulsion.     

华山松籽油理化性质及脂肪酸组成分析

华山松籽为我国特产,该文对华山松籽油理化性质和脂肪酸组成进行分析测定,该油不饱和脂肪酸含量近90％,γ-亚麻酸含量达15.79％,系为γ-亚麻酸很好来源。     

国内外亚硫酸化鱼油产品性能的差异

通过化学分析和皮革加脂实验，考察了进口和国产亚硫酸化鱼油在产品的外观状态，组分构成及加脂性能等方面的差异，分析了产生这些差距的基本原因，并从理论上提出了相应的解决措施，对国产亚硫酸化鱼油质量的改进与提高具有一定的指导意义。     

郫县豆瓣酱发酵过程中理化指标和生物胺变化及成本效益分析

郫县豆瓣酱具有独特的酯香,味道鲜美醇厚,是生活中不可或缺的调味料之一,郫县豆瓣酱中含有丰富的营养物质,主要包括氨基酸、脂肪和蛋白质等,能够预防多种人类疾病.郫县豆瓣酱一直以来的加工工艺主要以传统的酿造为主,工厂化的酿造很少,严重影响了郫县豆瓣酱的发展.该研究基于此,对郫县豆瓣酱发酵过程中各种理化性质和生物胺的变化进行了...     

Structured lipids obtained by chemical interesterification of olive oil and palm stearin

Interesterification of palm stearin (PS) with liquid vegetable oils could yield a good solid fat stock that may impart desirable physical properties, because PS is a useful source of vegetable hard fat, providing β′ stable solid fats. Dietary ingestion of olive oil (OO) has been reported to have physiological benefits such as lowering serum cholesterol levels. Fat blends, formulated by binary blends of palm stearin and olive oil in different ratios, were subjected to chemical interesterification with sodium methoxide. The original and interesterified blends were examined for fatty acid and triacylglycerol composition, melting point, solid fat content (SFC) and consistency. Interesterification caused rearrangement of triacylglycerol species, reduction of trisaturated and triunsaturated triacylglycerols content and increase in diunsaturated-monosaturated triacylglycerols of all blends, resulting in lowering of melting point and solid fat content. The incorporation of OO to PS reduced consistency, producing more plastic blends. The mixture and chemical interesterification allowed obtaining fats with various degrees of plasticity, increasing the possibilities for the commercial use of palm stearin and olive oil.     

Influence of SFC, microstructure and polymorphism on texture (hardness) of binary blends of fats involved in the preparation of industrial shortenings

Several binary blends of vegetable oils commonly used in industrial shortenings (i.e., palm oil (PO), hydrogenated palm oil (HPO), soybean oil (SO), hydrogenated soybean oil (HSO), low-erucic acid rapeseed oil (LERO), hydrogenated low-erucic acid rapeseed oil (HLERO)) were studied for their physical properties such as solid fat content (SFC) by nuclear magnetic resonance (NMR) and textural properties (hardness). Microstructure was also observed by microscopy in order to explain the variability in hardness for samples having the same SFC values. The blends studied by microscopy were the following: HSO, HPO and HLERO diluted in LERO. For these three blends which had the same SFC, the level of network structure was different. HSO diluted in LERO had more crystals, closer to each other and overlapped. This can explain that HSO has a higher hardness than HPO or HLERO, for a same SFC value, when diluted in LERO. Polymorphism was also observed by powder X-ray diffraction. The variability in hardness for samples having the same SFC is due to various crystal types and/or network structures that are formed upon crystallization of hard fats. This work demonstrates that for binary blends of studied oils, changes in the hardness are controlled mostly by the SFC, polymorphism and also by the material’s microstructure.     

Lipase-catalyzed production of solid fat stock from fractionated rice bran oil,palm stearin,and conjugated linoleic acid by response surface methodology

Solid fat stock was produced from the fractionated rice bran oil (solid phase, S-RBO) and palm stearin (PS) through lipase-catalyzed reaction, in which conjugated linoleic acid (CLA) was intentionally incorporated. For optimizing the reaction, response surface methodology (RSM) was employed with four reaction variables such as water activity, reaction temperature, reaction time, and mole ratio of S-RBO to PS. The predictive model was adequate due to no significant lack of fit and satisfactory level of coefficient of determination (R² = 0.95). The melting point of solid fat stock was affected by reaction time and substrate mole ratio, whereas water activity and reaction temperature had no significant effect. Based on ridge analysis, the combination of A_w (X₁; 0.32), reaction temperature (X₂; 65.3 °C), reaction time (X₃; 28.9 h), and substrate mole ratio (X₄; 1:1.1) was optimized for producing solid fat stock with target melting point of 43.8 °C. The solid fat stock (SFS) contained 39.9% palmitic, 31.3% oleic, 13.2% linoleic acid, and 10.9% CLA isomers. Solid fat contents were 23.4, 10.9, and 2.5% at 20, 30, and 40 °C, respectively. These results suggested that RSM can be used to optimize the lipase-catalyzed production of a solid fat stock.     

Pasting,Thermal, Hydration,and Functional Properties of Annealed and Heat-Moisture Treated Starch of Sword Bean (Canavalia gladiata)

The effects of annealing (ANN) and heat-moisture treatments (HMT) on the physicochemical and functional properties of Sword bean starches were investigated. The pasting properties differ significantly among the starches, with peak viscosity ranging from 399.17 RVU to 438.33 RVU; however, all the starches exhibited ‘Type C’ class with restricted swelling. The HMT starches had the highest gelatinization temperature, while change in enthalpy of gelatinization, ΔH_gel of the native starch, was higher (13.82 J/g) than that of the modified starches (1.39–6.74 J/g). The solubility and swelling power of all the starches increased as the temperature increased. The oil and water absorption capacity of the starches ranges between 3.24–3.91 g/g and 2.42–3.35 g/g, respectively. HMT (at 25 and 30% moisture level) changes the X-ray diffraction pattern of the starch from Type ‘B’ to Type ‘C’. The Scanning electron micrograph results revealed the starch granules with smooth ellipsoids and indentation in their centre, hydrothermal modification showed little effect on the morphology and size of the granules. Hydrothermal modification improved the physicochemical and functional properties of the starch without destroying the granule of the starch.     

三元体系Na~+/CO~(2-)_3,BORATE-H_2O298K相关系和溶液物化性质的研究

用等温溶解法测定了三元体系Ｎａ＋／ＣＯ２－３,ｂｏｒａｔｅ－Ｈ２Ｏ２９８Ｋ时的溶解度及其饱和溶液的物化性质（密度、折光率、粘度、电导率、ｐＨ值）,绘制出了相应的溶解度图和物化性质－组成图。此三元体系等温溶解度图属简单共饱型,平衡固相分别为Ｎａ２ＣＯ３．１０Ｈ２Ｏ和Ｎａ２Ｂ４Ｏ７·１０Ｈ２Ｏ,未产生新的复盐和固溶体。     

油脂氧化与抗氧化研究

本文从油脂氧化与抗氧化机理出发，以鱼油、猪油、花生油为例，对国内外常用的抗氧化剂进行了效能比较，为探索一条安全、高效、经济的抗氧化途径提供依据。     

Effect of Various Chemical Treatments of Prosopis juliflora Fibers as Composite Reinforcement: Physicochemical,Thermal, Mechanical,and Morphological Properties

ABSTRACT

The present environmental regulations enforced by the government authorities have made the investigators around the globe to make use of more and more green materials particularly in composite systems. In this context, natural fibers play an important role and proven to be excellent reinforcements in polymer matrices. However, these natural fibers have got one major limitation: their incompatible hydrophilic behavior which affects their bonding with hydrophobic matrixes. Researchers over the years have come up with several fiber surface modification processes to overcome this defect. So, in this present study, the effect of various chemical treatments like alkaline, benzoyl peroxide, potassium permanganate, and stearic acid on Prosopis juliflora fibers has been discussed. These various chemical treatments on the fiber surfaces impacted on their structure, composition, and properties which were discovered through chemical analysis, Fourier transform-infrared, X-ray diffraction, thermogravimetric analysis, differential scanning calorimetry, scanning electron microscopy, and tensile testing.     

Effect of heat-moisture treatment on the formation and physicochemical properties of resistant starch from mung bean (Phaseolus radiatus) starch

Mung bean starch was subjected to a range of heat-moisture treatments (HMT) based on different moisture contents (15%, 20%, 25%, 30%, and 35%) all heated at 120 °C for 12 h. The impact on the yields of resistant starch (RS), and the microstructure, physicochemical and functional properties of RS was investigated. Compared to raw starch, the RS content of HMT starch increased significantly, with the starch treated at 20% moisture having the highest RS content. After HMT, birefringence remained at the periphery of the granules and was absent at the center of some granules. The shape and integrity of HMT starch granules did not change but concavity was observed under scanning electronic microscopy. Apparent amylose contents of HMT starch increased and the HMT starch was dominated by high molecular weight fraction. Both the native and HMT starches showed A-type X-ray diffraction pattern. Relative crystallinity increased after HMT. The gelatinization temperatures (To, Tp, and Tc), gelatinization temperature range (Tc–To) and enthalpies of gelatinization (ΔH) increased significantly in HMT starch compared to native starch. The solubility increased but swelling power decreased in HMT starches. This study clearly shows that the HMT exhibited thermal stability and resistance to enzymatic hydrolysis owing to stronger interactions of starch chains in granule.