氧化深度对双变性淀粉与PVA混溶性的影响

通过改变氧化剂的用量,合成了一系列具有不同羧基含量的氧化乙酰化双变性淀粉浆料,然后以初显分离时间和沉降率为量化指标,分别研究了它们与ＰＶＡ－１７９９、ＰＶＡ－１７８８及ＰＶＡ－０５８８三种聚乙烯醇的浆液混溶性。试验结果表明,该双变性淀粉中的羧基含量对它一ＰＶＡ之间的浆液混溶性影响很大,提高氧化深度能够显著改善两者间的混溶性能,有助于进一步提高其上浆性能;ＰＶＡ分子结构则对这种混溶性的相对较小。     

新型氧化剂微波干法制备氧化淀粉及其性能研究

干法制备变性淀粉已逐步在国内推广,它具有流程短,能耗低,操作简便等优点。采用微波干法工艺,研究了二氧化氯、氯酸钠两种氧化剂制备氧化淀粉(分别为氧化淀粉A和氧化淀粉B)的工艺和变性淀粉的性能。工艺研究表明,两种氧化剂均能通过微波干法制备氧化淀粉,而氧化淀粉A和氧化淀粉B的羧基含量分别为(0.068±0.002)%和(0.586±0.002)%。性能研究表明,氧化淀粉的热黏度稳定性得到了改善,氧化淀粉B的冻融稳定性较好,经2次冻融,析水率仅为23.7%;氧化淀粉A耐碱性能好,耐酸性较差,氧化淀粉B则具有较好的耐酸耐碱性;X-射线衍射结果表明淀粉的氧化反应主要发生在淀粉的无定型区,而晶体结构仍与原淀粉相同。     

制备易消化氧化淀粉工艺条件的研究

本论文研究了不同条件对生成易消化氧化淀粉的影响。试验表明,以马铃薯淀粉为原料,NaClO为氧化剂时影响羧基含量和消化性能的因素中,以NaClO的影响最显著。通过正交试验确定了制备消化性能好的氧化淀粉的最佳工艺条件为:次氯酸钠用量3%,反应时间2h,反应温度30℃,pH10。通过研究氧化淀粉的羧基含量与消化性能的关系,发现其在一定范围内呈正相关性。     

交联氧化乙酰化蜡质玉米淀粉性质的研究

以蜡质玉米淀粉为原料、三偏磷酸钠为交联剂、次氯酸钠为氧化剂、醋酸酐为乙酰化试剂,采用湿法工艺制备交联氧化乙酰化复合变性淀粉,并利用扫描电镜(SEM)及红外光谱仪(FT-IR)分析其淀粉颗粒的形貌及结构。结果显示:复合变性处理后的淀粉白度升高至97.2,糊透光率升高至71.0%,耐酸及抗剪切性能也有所改善。扫描电镜图表现了淀粉颗粒形貌的变化,红外光谱图中展现的各基团的特征吸收峰表明其分子结构发生了改变。蜡质玉米淀粉采用复合变性的处理手段,有益于增强其在食品加工领域的应用价值。     

复合稳定剂对豇豆饮料稳定性的影响

以优质花豇豆为原料,采用均匀设计法,以获得最佳的稳定剂添加量。结果表明,所选稳定剂最佳添加量为黄原胶0.10%,氧化羟丙基变性淀粉0.12%,乙酰化二淀粉磷酸酯淀粉0.32%。按该比例所得豇豆饮料稳定性好,感官品质佳。     

微波氧化过程对氧化淀粉阻垢性能的影响

以玉米淀粉为原料,采用微波处理方式,以双氧水为氧化剂,对玉米淀粉进行改性,引入羧基、羰基等官能团,缩短氧化反应时间,得到高羧基含量、少盐残的氧化淀粉阻垢剂。通过微波功率、氧化剂用量、水分含量等单因素实验,研究其对氧化淀粉阻垢性能的影响,得出羧基含量、羧基-羰基比与氧化淀粉阻垢性能呈正相关。通过监测微波反应过程中水分含量、羧基、羧基-羰基比例的变化过程,反映淀粉微波氧化反应过程中的条件变化(水分含量、p H、温度)对氧化淀粉的氧化程度、溶解度、阻垢性能的影响机制。得到了冷水可溶、高阻垢性能的氧化淀粉。     

梭子蟹浓缩汁加工工艺的研究

以冰鲜梭子蟹为原料,研究料液比、熬煮时间和熬煮次数对梭子蟹浓缩汁氨基态氮和蛋白质含量的影响,并以感官评定为指标,对变性淀粉、黄原胶和乙酰化双淀粉己二酸酯等增稠剂的配比进行优化。结果表明,在料液比为1︰8(g/mL),熬煮时间为90 min,熬煮次数为2次时,梭子蟹浓缩汁的氨基态氮和蛋白质含量最高。在梭子蟹浓缩汁中添加4.0%变性淀粉、0.1%黄原胶和0.1%乙酰化双淀粉己二酸酯具有令人满意的产品属性和产品品质。在该条件下制得的产品不仅拥有梭子蟹特有的风味更保留了其营养成分,为梭子蟹的综合应用提供了理论依据和实践经验。     

烯基琥珀酸淀粉酯乳液喷干微胶囊化关键技术

烯基琥珀酸淀粉酯是一类亲油性变性淀粉,具有优越的乳化性能。特别是低粘度辛烯基琥珀酸淀粉酯由于其卓越的乳化和成膜性能、高的包埋效率、低的表面油、易干燥特性、高固形物时低粘等优点,已成为一种食品中重要的微胶囊壁材。但是此类变性淀粉最致命的不足是当其微胶囊化易氧化的芯材时,微胶囊化产品的氧化稳定性很差。为此,在微胶囊化时采取芯材稳定化、壁材复配、合理乳化、优化喷干工艺等关键技术尤为重要。     

不同原料双氧水氧化淀粉的制备及性能

研究了不同原料(蜡质玉米淀粉、木薯淀粉、玉米淀粉、小麦淀粉)双氧水氧化淀粉的制备及工艺条件的优化,对不同原料氧化淀粉的性能进行分析,并从中得出如下结论:不同原料氧化淀粉产品的分子质量随羧基质量分数的增大而降低,粘度随羧基质量分数的增大而下降,糊的透明度随羧基质量分数的增大而增大。     

乙酰化酸解糯玉米变性淀粉的制备及性能研究

以糯玉米淀粉为原料,盐酸为酸解剂,醋酸酐为酰化试剂,氢氧化钠为催化剂,无水硫酸钠为膨胀抑制剂,对乙酰化酸解糯玉米变性淀粉的制备工艺及性能进行研究。考察反应时间、反应温度、醋酸酐用量、pH值、无水硫酸钠用量对乙酰化酸解糯玉米变性淀粉取代度的影响。结果表明,各因素对酸解糯玉米淀粉的乙酰化 反应均有影响,最佳制备条件为反应温度25℃、反应时间50min、pH8.5、无水硫酸钠用量1.5%。酸解糯玉米淀粉经乙酰化后,其糊透明度、冻融稳定性均增加,且随着取代度的增大而增加,但乙酰化对凝沉性无影响。     

改性淀粉基鲢鱼油皮克林乳液的制备及其理化特性研究

为提高鲢鱼鱼糜加工副产物-鲢鱼脂肪的利用率,以六种改性淀粉为固体颗粒、鲢鱼油为油相制备皮克林乳液,考察了淀粉种类、淀粉添加量(1%、2%、3%、4%、5%,w/w)、油水比(0.1、0.2、0.3、0.4、0.5、0.6,w/w)和离子强度(氯化钠浓度:0、0.1、0.2、0.3、0.4、0.5 mol/L)对乳液的理化特性(粒径、Zeta电位、乳化特性、稳定性、流变特性、微观结构)的影响。结果表明,六种改性淀粉中,辛烯基琥珀酸玉米淀粉颗粒粒径最小(146.73 nm),接触角最大(71.5°),制备的皮克林乳液最稳定。油水比和淀粉添加量显著影响了乳液的理化特性,较高的油水比(0.5～0.6)和淀粉添加量(4%～5%)使乳液表现出凝胶特性,适量(0.3～0.5 mol/L)氯化钠的添加可促进乳液微絮凝,增强乳液稳定性。乳液CLSM观察微观结构发现,乳液液滴的粒径随淀粉添加量的增加而减小,在2%～5%淀粉添加量下可观察到油滴被淀粉颗粒完全包裹,形成了致密的界面膜。油水比、淀粉添加量和氯化钠浓度分别为0.5、4%和0.4 mol/L时,乳液性能较佳。本研究可为功能性乳液配料的制备及其在功能...     

Hypochlorite oxidation of field pea starch and its suitability for noodle making using an extrusion cooker

The effect of hypochlorite oxidation on the Brabendar pasting properties of field pea starch and the suitability of native and oxidized starch for noodle making by extrusion cooking were investigated. Field pea starch was oxidized with sodium hypochlorite at a level of active chlorine ranging from 0.89 to 3.28% (starch db). The degree of oxidation was determined and expressed in terms of percentage of carboxyl and carbonyl groups, which ranged from 0.02 to 0.38% and 0.06 to 0.19%, respectively. Starch recovery and peak viscosity, hot paste viscosity, cool paste viscosity, and setback of oxidized starches decreased with increasing degree of oxidation. The cooking quality attributes of noodles prepared from native field pea starches were acceptable but were negatively influenced by hypochlorite oxidation. Substitution of potato starch (40%, db) for field pea starch yielded more glossy noodles with better cooking quality. It was also observed that Brabendar pasting properties had high correlations with noodle quality characteristics.     

The choice of homogenisation equipment affects lipid oxidation in emulsions

Milk proteins are often used by the food industry because of their good emulsifying properties. In addition, they can also provide oxidative stability to foods. However, different milk proteins or protein components have been shown to differ in their antioxidative properties, and their localisation in emulsions has been shown to be affected by the emulsification conditions. The objective of this study was to investigate the influence of homogenisation equipment (microfluidizer vs. two-stage valve homogeniser) on lipid oxidation in 10% fish oil-in-water emulsions prepared with two different milk proteins. Emulsions were prepared at pH 7 with similar droplet sizes. Results showed that the oxidative stability of emulsions prepared with sodium caseinate was not influenced by the type of homogeniser used. In contrast, the type of homogenisation equipment significantly influenced lipid oxidation when whey protein was used as emulsifier, with the microfluidizer resulting in lower levels of oxidation.     

疏水改性藜麦淀粉的制备及其Pickering乳液乳化性研究

本文用碱提法从藜麦种子中提取藜麦淀粉,并用辛烯基琥珀酸酐(Octenyl Succnic Anhydride,OSA)对提取的藜麦淀粉进行疏水改性,得到了辛烯基琥珀酸淀粉酯(OSA淀粉)。通过傅里叶红外光谱、扫描电子显微镜对比原淀粉和OSA淀粉颗粒的结构和形态,发现OSA基团成功接到淀粉表面,在形态上表现为颗粒表面轻度破坏。通过测定乳液微观结构,乳滴粒径及乳化指数(EI),分析了OSA淀粉取代度、颗粒浓度和油相比例等因素对Pickering乳液乳化性的影响。结果表明,乳滴粒径随OSA淀粉取代度或淀粉颗粒浓度的增加而减小、EI值随OSA淀粉取代度或淀粉颗粒浓度的增加而提高,乳液乳化性增强。当油相比例的增加时,乳滴粒径增大,且在食品添加剂允许OSA添加量的范围内,取代度为1.43%的OSA淀粉颗粒的EI值达到最大值75.48%,乳化性最好。研究表明OSA改性藜麦淀粉作为Pickering乳液的稳定颗粒在食品领域有极大的应用潜力。     

氧化程度对羧酸型两性淀粉性能的影响

氧化型两性淀粉是一种新型的两性淀粉,同时包含羧基和阳离子基团。其制备采用两步法,先将淀粉阳离子化,再将阳离子淀粉氧化。阳离子淀粉最佳制备工艺为:淀粉乳浓度35%,醚化剂的用量为5%,pH11.6,反应先在50℃活化2h,再降温到45℃反应8h。通过添加不同量的NaClO到阳离子淀粉中制得羧基含量不同的两性淀粉,所得淀粉洁白,糊透明度高,稳定性强,凝沉性弱,热糊粘度也较阳离子淀粉明显下降,且这些性能均随羧基含量的增加而增强。     

Partial Characterization of Tamarind (Tamarindus indica L.) Kernel Starch Oxidized at Different Levels of Sodium Hypochlorite

The effects of different levels of sodium hypochlorite (1–4 g/100 g dry solids active chlorine) on the physicochemical, pasting, and structural properties of tamarind kernel starches were investigated. The isolated starch had low traces of non-starch components, such as protein, fat, and ash, indicating its purity. Both the carboxyl and carbonyl contents in the oxidized starches increased significantly with the increase in chlorine concentration. The introduction of carboxyl and carbonyl groups resulted in significantly lower amylose content. The swelling power of oxidized starches was significantly lower than native starch and the solubility values increased when the chlorine concentration increased at all the measured temperatures. The percentage of light transmittance increased progressively after oxidation. Pasting properties showed that in treatments at high active chlorine concentrations, the peak viscosity decreased more drastically than in treatments at low chlorine concentration, indicating a greater degradation of starch. The morphology of the starches was not altered after oxidation. After oxidative treatment no change in the X-ray diffraction pattern was observed but intensity of the peaks increased. Therefore, tamarind kernel being underutilized raw material, has a great potential as a non-conventional source of starch and desirable properties of this starch can be enhanced by oxidation for applications in food industry.     

Pulsed electric field-assisted glycation of bovine serum albumin/starch conjugates improved their emulsifying properties

In this study, pulsed electric field (PEF, at electric field strengths from 3.5 to 8.1 kV/cm, pulse duration (τ) = 50 μs) was used to assist the glycation between soluble potato starch and bovine serum albumin (BSA). Moreover, the physicochemical and stability of BSA/starch conjugates emulsions were characterized. Spectroscopic investigations (A₄₂₀ and UV–Vis spectra) proved that PEF treatment (3.5–5.7 kV/cm) facilitated Maillard reaction between BSA and soluble starch. Moreover, the grafting degree (%) and the protein solubility of BSA/starch conjugates increased after PEF treatment but declined at higher electric field strengths. PEF treatment (at 3.5–5.7 kV/cm) decreased the particle sizes, surface hydrophobicity and fluorescence emission intensity of BSA/starch conjugates. Furthermore, emulsions stabilized by PEF-treated conjugates (at electric field strengths 3.5–5.7 kV/cm) exhibited smaller droplet sizes and higher adsorbed protein (AP%), indicating improved emulsion stability. Similarly, emulsions stabilized by PEF-induced conjugates (at electric field strengths 3.5–5.7 kV/cm) had better stability at pH = 4.6 and against different ionic strengths (150-300 mM NaCl). Differential scanning calorimetry (DSC) patterns showed that emulsions stabilized by PEF-treated conjugates had better freeze-thaw stability. In conclusion, PEF as a green technology could assist glycation and enhance the emulsifying properties of protein-polysaccharides conjugates.Industrial relevanceApplying green technologies in the food industry is critical for sustainable food production. As an eco-friendly food processing approach, PEF has been utilized in food industries to inactivate enzymes and microorganisms without affecting the nutritional quality of treated foodstuffs. Moreover, emulsions are widely applied in the food, drug delivery, and pharmaceutical industries. In our research, PEF could facilitate the Maillard reaction between soluble starch and BSA and improve the emulsifying properties of BSA/soluble starch conjugates. The results of this work could provide fundamental information on the mechanism of PEF-induced Maillard reaction and how PEF can improve the emulsifying properties of the conjugates. Thus, this work could help for increasing PEF applications in the food industries.     

Emulsifying properties of gum kondagogu (Cochlospermum gossypium), a natural biopolymer

BACKGROUND: Natural polymers are widely used as emulsifying agents in the food and pharmaceutical industries because of their low cost, biocompatibility and non‐toxic nature. In the present study, emulsifying properties of the novel natural biopolymer gum kondagogu (GKG) were investigated. GKG solutions of different concentrations (0.1–0.6% w/v) were prepared in water and emulsified with liquid paraffin oil (40% v/v) in a high‐speed homogeniser. Flow properties of the emulsions were measured using a rheometer. Emulsion stability and droplet size distribution were determined by visual observation, photomicrography and laser‐scattering particle size distribution analysis. RESULTS: The emulsions prepared with GKG showed pseudoplastic behaviour. The size of oil droplets and the viscosity of emulsions at concentrations of 0.4–0.6% w/v showed little change over time (up to 30 days), indicating that the emulsions were stable. Measurements of the zeta potential of emulsions adjusted to different pH, with and without added electrolyte, showed that the stabilisation of emulsions with GKG was due to mutual repulsion between electrical double layers of particles and adsorption of macromolecules on oil droplets. CONCLUSION: The results of this experimental investigation show that GKG is a good emulsifying agent even at low concentrations, with many potential applications in the food and pharmaceutical industries. Copyright © 2009 Society of Chemical Industry     

臭氧处理对糯米品质的影响及其机理

采用质量浓度为5 mg/L的臭氧作为氧化剂,对糯米整米通气氧化后制作水磨糯米粉并且提取相对应的糯米淀粉。通过实验发现氧化后糯米粉及对应提取的糯米淀粉随着臭氧处理时间的增长糊化黏度呈增大趋势,但热糊稳定性和抗老化性有略许减弱,蒸煮特性未发生较大变化。羧基含量随着氧化时间的增长而增大,而羰基含量随着氧化时间的增长呈先增后减的趋势。通过红外光谱分析发现臭氧将糯米淀粉中葡萄糖单元上C2、C3和C6的羟基先氧化为羰基,随着氧化作用的加强羰基被氧化成为羧基,但由于是对于糯米的氧化处理,因此在反应中会生成部分酰胺,同时葡萄糖环中的C-O-C未发生断裂。