Effect of different treatments on the microstructure and functional and pasting properties of pigeon pea (Cajanus cajan L.), dolichos bean (Dolichos lablab L.) and jack bean (Canavalia ensiformis) flours from the north‐east Argentina

The effect of germination (G; 5 days), soaking‐cooking (SC; 6 h–20 min, 6 h–40 min, 6 h–60 min) and microwave (M; 50%, 70%, 100%) treatments on pigeon pea (PP), dolichos bean (DB) and jack bean (JB) seeds was studied. Microstructure of seeds and functional (protein solubility, water‐holding capacity, oil‐holding capacity, emulsion stability) and pasting properties of flours were determined. Germination and microwave treatments modified the protein matrix of cotyledon cells preserving the shape of the starch granule, whereas the SC treatment (6 h–60 min) affected both. The soaking‐cooking is the most influential treatment on the functional properties of PP, DB and JB flours, as increased water absorption capacity (73–96%), decreased protein solubility (>80%) and the tendency to retrogradation of amylose (69–85%) also improved emulsion stability.     

Gelation,thermal and pasting properties of pigeon pea (Cajanus cajan L.), dolichos bean (Dolichos lablab L.) and jack bean (Canavalia ensiformis) flours

This study evaluated the rheological, thermal and pasting properties of pigeon pea (PP), dolichos bean (DB) and jack bean (JB) legume flours and gels. Starch and protein contents were also measured and its molecular weight distribution was determined by electrophoresis. PP and DB showed the highest viscosities while JB had the highest pasting temperature. The minimum flour concentrations for gel formation were estimated at 6–8% for DB and PP and 10% for JB. Above these concentrations all flour suspensions heated to 95 °C led to gels with a solid-like behavior. Differential scanning calorimetry showed two endothermic peaks in all flours at 80–89 °C and 96–100 °C. Avrami model was successfully fitted to the hardening kinetics of PP and DB gels stored at 4 °C. The half-life times were 22 and 6 h for PP and DB respectively. PP and DB flours were able to form self-supporting gels and could be applied in the formulation of gel-like foods.     

In vitro digestibility,structural and functional properties of starch from pigeon pea (Cajanus cajan) cultivars grown in India

Starches isolated from two pigeon pea cultivars (AL-15 and AL-201) were evaluated for their in vitro digestibility, structural and functional properties. Both the cultivars exhibited a characteristic C-type diffraction pattern with relative crystallinity values of 31.9% and 34.2%, for AL-15 and AL-201, respectively. The structural characterization obtained using high performance size exclusion column chromatography revealed that molecular weight of amylopectin and amylose was higher for AL-201 (396 and 3.92 × 10⁶ g/mol, respectively) in comparison to AL-15 starch (354 and 3.31 × 10⁶ g/mol, respectively). AL-201 exhibited higher values for transition temperatures, enthalpy of gelatinization, pasting temperature and percentage retrogradation in comparison to AL-15 starch. Slowly digestible starch, readily digestible starch and resistant starch contents of AL-15 and AL-201 cultivars were observed to be 31.0, 8.1 and 60.9% and 29.6, 5.2 and 65.2%, respectively. The hydrolysis index and RS values indicated that pigeon pea starches were highly resistant to digestion.     

超声波处理对豌豆淀粉糊化、流变及质构特性的影响

以豌豆淀粉为原料,分别用0,150,300,450 W的超声波进行处理,考察超声波处理对豌豆淀粉糊化、流变及质构特性的影响。结果表明:超声波处理对豌豆淀粉的糊化、流变及质构特性都有较大影响。随着超声波功率的增加,豌豆淀粉糊峰值黏度、终值黏度、崩解值及回升值都显著下降,使豌豆淀粉冷稳定性及热稳定性得到提升;稠度系数k减小,流体指数n增大,触变性减小,流动性增加,使豌豆淀粉流变稳定性提高;G′与G″减小,tanδ增大,使豌豆淀粉黏弹性降低。此外,超声作用使豌豆淀粉凝胶的硬度、弹性、内聚性、胶着性及咀嚼性都呈下降趋势,其中硬度与胶着性下降最显著。扫描电镜表明,超声波对豌豆淀粉产生破坏作用,使淀粉颗粒表面出现坑洞及皱褶,部分颗粒结构变得不完整。     

Review: regulation on structure,rheological properties and aroma volatile compounds of fermented chickpea milk by enzymatic catalysis

The effects of enzymolysis with four different enzymes on the free amino acid content (FAA) and protein subunit composition (SDS-PAGE) of chickpea milk, as well as the rheological behaviour, microstructure and aroma volatile compounds of fermented chickpea milk (FCM), were investigated. After enzymatic catalysis, 7S and 11SA globulin were all slightly degraded and a certain amount of free amino acids could be released. Moreover, FCM with enzymolysis possessed lower elastic modulus (G′) and viscous modulus (G″) than FCM. The SEM micromorphology and rheological characteristics of FCM hydrolysed with papain (C₁ FCM) were substantially improved. Principal component analysis (PCA) results grounded on E-nose can distinguish the flavour changes in FCM with enzymolysis to some extent. Totally, sixty-six volatile aroma compounds were detected by GC-MS. The varieties of volatile aroma compounds in C₁ FCM (41) were more than that in FCM (24). These findings indicated that enzymolysis, especially with papain, could be used as an effective method to improve the structure, rheological characteristics and flavour of FCM.     

红茶水提物对大米淀粉糊化、流变和老化特性的影响

研究红茶水提物对大米淀粉糊化、流变、老化、晶体结构和微观结构等影响。结果表明,红茶水提物总酚和总黄酮含量分别为2 960.20、1 540.73μg/mL,红茶水提物含没食子酸、儿茶素、表没食子儿茶素没食子酸酯、表儿茶素没食子酸脂、咖啡因。红茶水提物降低大米淀粉糊化焓值(ΔH),100∶20实验组相比于对照组降低了22.10%,红茶水提物降低淀粉凝胶强度,在扫描频率为55 rad/s时,100∶20实验组淀粉凝胶的G′相比于对照组降低了37.5%;红茶水提物抑制淀粉老化,抑制效果随着水提物浓度增加而增大,在老化1 d时,100∶20实验组的硬度值相比于对照组降低了33.81%,但抑制效果随老化时间延长而减弱,红茶水提物对淀粉凝胶的溶解度、膨胀度和晶体结构没有产生显著的影响。     

微波复合酶解改性对小米淀粉结构表征及其理化特性的影响

本文以小米淀粉为原料,采用微波、酶解、微波复合酶解三种方法改性淀粉。从淀粉颗粒形貌、偏光特性、结晶结构、短程有序性、粒径分布等方面对小米淀粉进行结构表征,测定其直链淀粉含量、溶胀力与透明度等指标以分析小米淀粉的理化特性。结果表明：改性后,小米淀粉的颗粒结构被破坏,偏光十字特性消失,结晶结构发生改变,但三种改性方法均不影响小米淀粉的基本官能团。其中,微波改性小米淀粉为A型晶体,酶解和微波复合酶解改性淀粉结晶型为B型,微波复合酶解改性淀粉的相对结晶度提高了35.32 %。改性淀粉的粒径、直链淀粉含量均有所提高,与原淀粉相比,微波复合酶解改性淀粉的直链淀粉含量增加了49.03 %。综上所述,与单一法相比,微波复合酶解法对淀粉颗粒结构和理化性质的改善效果最佳,这对于小米淀粉基食品的开发应用具有重要意义。     

Hydroxypropylation of pigeon pea (Cajanus cajan) starch: Preparation, functional characterizations and enzymatic digestibility

Hydroxypropyl starch derivatives were prepared from pigeon pea starch (NPPS) which is an unconventional starch source. Functional parameters and characterization of both native and modified starches were carried out. The starch granules appeared oval or elliptical in shape with sizes ranging from 7 to 40 μm in width and 10 − 30 μm in length. Hydroxypropylation did not alter the shape of the starch granules in a pronounced way. Generally, the x-ray diffractograms of native pigeon pea starch showed the “A” pattern. However, slight reductions in the diffraction intensity of starches after modification were observed. At all temperatures studied (30-90 °C), swelling and solubility of hydroxypropylated starches were higher than the NPPS. Progressive increases in swelling capacity and solubility were observed as the molar substitution (MS) increased among the hydroxypropylated starches. Hydroxypropylation reduced starch paste turbidity on storage. Also, studies showed that syneresis reduced after hydroxypropylation. In addition, syneresis reduced as the MS of the hydroxypropyl starches increased. The results indicate that pasting temperature and peak temperature reduced after modification but peak viscosity increased in hydroxypropylated starch derivatives compared with the native starch. Setback reduced in hydroxypropylated starches compared with the native starch. Enthalpy of gelatinization and percentage retrogradation reduced after hydroxypropylation and progressive reductions were observed as the MS increased among the starch derivatives. Hydroxypropylation increased enzymatic digestibility.     

酶解—磷酸化协同改性对卵白蛋白特性与结构的影响

为考察酶解和磷酸化协同改性对卵白蛋白特性和结构的影响,针对酶解和磷酸化协同改性的卵白蛋白的功能特性变化进行分析,并通过FT-IR、DSC和SEM对协同改性的卵白蛋白结构变化进行分析。结果表明,协同改性后的卵白蛋白的溶解度、凝胶强度、乳化性较酶解后的和未改性的卵白蛋白都有较大的提高,但起泡性和泡沫稳定性有所降低;结构上,卵白蛋白因酶解导致其肽链发生断裂,使得更多的氨基酸残基暴露出来,α-螺旋和β-折叠均有所增加;协同改性的卵白蛋白热变性温度较酶解的和未改性的卵白蛋白分别升高了7.13,10.19℃;此外,由于磷酸基团的嵌入,使蛋白的结构发生了变化,分子结构由球状体变成了层叠的片状结构。     

牛骨胶原蛋白酶解工艺优化及结构特性分析

为研究前期纯化的特异性降解牛骨胶原蛋白的胶原蛋白酶(BSC)对牛骨胶原蛋白的酶解工艺,以水解度为响应值,在单因素试验基础上通过五元二次正交旋转组合试验,确定最佳酶解工艺为:反应温度46℃、牛骨胶原蛋白添加量5.14g/100mL、BSC添加量0.42g/100 mL、反应时间6h、pH 6.5,该工艺条件下水解度为34.98%。采用紫外光谱(UV)、荧光光谱(FS)、傅里叶红外光谱(FT-IR)、扫描电镜(SEM)对牛骨胶原蛋白及其产物进行结构特性分析。通过UV分析表明BSC酶的降解作用破坏了牛骨胶原蛋白的三股螺旋结构,游离出大量的氨基酸;FS分析表明牛骨胶原蛋白分子表面C═O、CONH_2、COOH逐步增多,胶原蛋白肽中生色基团分布也随之发生变化;FT-IR分析可知牛骨胶原蛋白经降解后的胶原蛋白肽的肽链上—NH_2~+—排斥作用逐渐减弱,主要以β-转角为主;SEM表明酶破坏了牛骨胶原蛋白的表面分子结构,使其变得疏松。     

超声改性蛋白对玉米淀粉凝胶结构及消化特性的影响

为探究超声改性蛋白对玉米淀粉凝胶结构及消化特性的影响规律,将不同超声时间处理的大豆分离蛋白分别添加至玉米淀粉中,利用傅里叶红外光谱仪、差示扫描量热仪、X-射线衍射仪及流变仪等表征超声改性蛋白与玉米淀粉复配凝胶体系结构,并对其体外消化特性进行分析。结果表明：与原玉米淀粉相比,当淀粉中添加不同超声时间处理的大豆分离蛋白后,玉米淀粉的短程有序性、分子内和分子间氢键强度、糊化焓值(ΔH)均降低,且随着超声时间的延长,呈逐渐降低趋势,当超声时间达到30 min时,复配体系的ΔH降低了27.27%;超声改性蛋白与玉米淀粉间相互作用主要通过疏水作用力;复合凝胶体系的X-射线衍射图显示出典型Ⅴ型结构特征,说明改性蛋白的加入改善了淀粉消化特性,与原淀粉相比,慢消化淀粉和抗性淀粉含量均随着超声时间的延长逐渐升高,慢消化淀粉和抗性淀粉质量分数分别提升了7.01%和3.41%。研究结果旨在为改性蛋白在淀粉基食品中的应用提供理论依据。     

Influence of wheat starch on rheological,structural and physico-chemical properties gluten–starch dough during mixing

This study mainly explored that the influence of wheat starch source on the rheology behaviours and structural properties of gluten–starch dough, and then the model doughs were prepared by the AK58 wheat gluten and three types of starches from strong (ZM366S), medium (AK58S) and weak gluten wheat (ZM103S) during mixing were studied. The damaged starch content of wheat starch was positively correlated with the wheat gluten strength, while the granule size was negatively. The G', G" and the extension resistance of ZM366S dough were higher than those of other doughs, which implied the source of starch also had a significant influence on the rheological properties. CLSM also observed that ZM366S was more closely bound to the gluten protein network. The glutenin macropolymer (GMP) content of ZM366S model dough was the highest, while the SH content was the lowest. Decreases in elasticity, extension and GMP, and small increase in SH content were displayed during dough mixing. Molecular forces were varied with different wheat starch and mixing time. The covalent bond was the main force between ZM103S and gluten, whereas the hydrogen and covalent bonds were the main force between ZM366S or AK58S and gluten. The interactions between ZM366 starch and gluten were stronger than others starch.     

Physicochemical,crystalline, and thermal properties of native and enzyme hydrolyzed Pueraria lobata (Willd.) Ohwi and Pueraria thomsonii Benth. starches

Starches isolated from the bulbs of Pueraria lobata (Willd.) Ohwi (PLO) and Pueraria thomsonii Benth. (PTB) were hydrolysed by glucoamylase for different lengths of time (2, 4, 8, 12, and 24 h). The hydrolysis results were compared by scanning electron microscope (SEM), X‐ray power diffractometer (XRD), and differential scanning calorimetry (DSC). The SEM results revealed that both of the PLO and PTB starches showed the same hydrolysis mechanism, which indicated that the glucoamylase primarily attacking the exterior of starch granules and then the interior. The results of XRD revealed the crystalline type of PTB starch changed from C‐type to A‐type with crystallinity reducing from 43.5 to 20.9% during the hydrolysis. Unlike PTB starch, the PLO starch did not show marked changes in crystalline style but lower degree of crystallinity was obtained from 32.4 to 13.7% during the hydrolysis. All the XRD results demonstrated that B‐type polymorph was preferentially degraded than A‐type polymorph in the C‐type starch. The DSC results revealed that both of the PLO and PTB starches showed decreased enthalpy of gelatinization (ΔH_gel) and gelatinization temperature range (R)‐value after hydrolysis, while the gelatinization temperature (T_p) indicated different tendency, initially ranging from 68.6 to 64.3°C and then increasing to 67.8°C for PLO starch. While for PTB starch, the T_p‐value showed progressive reduction from 85.4 to 74.3°C during the whole process.     

Application of ultrasound treatment for modulating the structural,functional and rheological properties of black bean protein isolates

The modulating effect of ultrasound treatments at varying powers and times on the structural and functional properties of black bean protein isolate (BBPI) was investigated. Compared with native BBPI, low-power (150 W) and medium-power (300 W) ultrasound treatments increased the solubility, foaming and emulsifying properties of BBPI, especially at 300 W, 24 min. This effect arises predominantly due to increased exposure of hydrophobic groups, which serve to increase the interactions between the protein and water molecules. Additionally, an increase in the protein surface activity improved the absorption of protein molecules at the oil–water and air–water interfaces. Rheology data showed that increased hydrophobic and hydrogen-bonding interactions improved the water-holding capacity of BBPI gels following ultrasound treatment. However, high-power (450 W) ultrasound treatment weakened the functional properties of BBPI, and this was likely due to the formation of macromolecular BBPI aggregates. Overall, this study indicates that ultrasound treatment could be a promising approach for modulating other plant protein resources as well as expanding the application of black bean protein.     

蛋白质、脂肪对豆类理化特性及体外消化特性的影响

以鹰嘴豆、花芸豆为原料,制备了脱脂豆类粉、脱蛋白豆类粉及豆类淀粉;研究了天然蛋白质、脂肪对豆类粉理化特性、体外淀粉消化速率及估计血糖生成指数的影响。经不同处理后,样品在化学组成、溶解度、糊化特性等方面均有显著差异,尤以豆类粉和豆类淀粉之间的差异最为显著。试验结果表明豆类粉的淀粉水解速率低于脱脂豆类粉、脱蛋白豆类粉和豆类淀粉,蛋白质含量、蛋白质/淀粉与估计血糖生成指数(eGI)呈极显著负相关,脂肪含量、脂肪/淀粉与eGI无显著相关性。