Physiochemical, antioxidant and whitening properties of extract from root cortices of mulberry as affected by membrane process

Extract from root cortices of mulberry (Morus alba, L.) was separated into permeate and retentate fractions using a membrane system equipped with either a microfiltration membrane or one of four molecular weight cut-off ultrafiltration membranes. The effects of membrane process at volume concentration ratio (VCR)=4 on the physiochemical characteristics, the contents of active compounds, antioxidant ability, and whitening capability (tyrosinase inhibitory activity) in permeate and retentate were evaluated. The clarification degree, antioxidant effects, and whitening capability of the permeates increased as compared to those of feed. In addition, permeate treated with a 0.45 μm microfiltration membrane exhibited less fouling layer and specific resistance (αpC_B=622.8 m⁻²×10⁻⁶) and thus had a higher permeate flux than treated with other ultrafiltration membranes (αpC_B=786.1-1025.3 m⁻²×10⁻⁶). A higher content of active compounds, such as chlorogenoic acid and p-hydroxybenzoic acid may explain higher antioxidant and whitening capabilities in permeate of extracts from root cortices of mulberry.     

快速制浆工艺豆渣中大豆膳食纤维物化特性的研究

该试验以快速制浆工艺产生的豆渣为原料制备大豆膳食纤维,分析比较了膳食纤维物化性质的变化。结果表明,与传统制浆工艺豆渣中大豆膳食纤维相比,快速制浆工艺豆渣中大豆膳食纤维的可溶性膳食纤维含量提高29.8%,持水性和膨胀性分别提高31.1%和50.0%,持油性下降了7.0%;pH值为7.0时,其溶解度为10.58 g/100 mL,溶解度对温度的敏感度降低,色泽明显亮白。扫描电镜结果显示,快速制浆工艺豆渣中大豆膳食纤维结构断裂明显,表面均匀性下降,因此具有更强的水化性能。     

不同分子量大豆可溶性膳食纤维对大米淀粉糊化及流变性质的影响

为了考察不同分子量大豆可溶性膳食纤维(soybean soluble dietary fiber,SSDF)对大米淀粉(rice starch,RS)糊化及流变性质的影响,本文采用快速黏度分析仪(RVA)及流变仪研究了两种分子量段(HSSDF,27.8 ku和LSSDF,9.3 ku)大豆可溶性膳食纤维的作用。RVA曲线表明添加HSSDF可提高RS的峰值黏度及最终黏度,添加LSSDF可使RS的最终黏度值降低,而峰值黏度无明显变化。两种不同分子量段的SSDF均可提高RS的起始糊化温度,降低回复值及崩解值。动态流变学实验表明,添加两种不同分子量段SSDF均可显著降低RS的储能模量值。静态流变学实验表明,添加HSSDF可使RS的稠度系数K升高,混合体系具有更高的黏度。加入两种不同分子量段的SSDF均可使混合体系流体指数n值降低,触变环面积减少,体系更加稳定。研究表明不同分子量段SSDF对RS复合体系糊化及流变学特性有显著影响,且HSSDF对大米淀粉的作用更为显著。本论文可为大豆膳食纤维在大米制品中的应用提供一定的理论基础。      

可溶性大豆膳食纤维的单糖组分分析及物性测定

采用气相色谱,对使用磷酸盐缓冲溶液提取-超滤纯化法从大豆渣、大豆皮中提取到的大豆膳食纤维(SSDF)产品进行了单糖组分测定.结果表明,大豆渣SSDF产品中所含的果胶类多糖的支链较少,淀粉和纤维素这两类多糖含量很低.而大豆皮SSDF产品中所含的果胶类多糖以高支链果胶多糖为主.对获得的SSDF产品,进行了流变性、溶解度、色泽稳定性、吸油性和阳离子交换能力的测定,并研究了影响其物性的因素.结果表明,从大豆渣中提取的可溶性大豆膳食纤维(SSDF)产品的溶解性好.其水溶液黏度小,溶液黏度受酸、碱、盐的影响较小.SSDF水溶液经长期煮沸后,仍能保持色泽不变.大豆渣SSDF的阳离子交换能力、吸油性均比大豆皮SSDF的高.     

Impact of dietary fibers on the properties and proteolytic digestibility of lactoferrin nano-particles

The application and development of biopolymer-based particulate delivery systems is receiving considerable attention from scientists and manufacturers seeking to engineer healthier and safer foods. Present work focused on the fabrication and proteolysis of bovine lactoferrin nano-particles onto which pectins, alginate and carrageenan were electrostatically deposited. DLS, CD and AFM were used to ascertain the formation of spherical structures with varying zeta potentials and modified protein folding. SDS-PAGE analyses of samples collected during simulated human gastro-duodenal digestion revealed that in the case of high and low methoxy pectin particle zeta potential values (−35.4 mV and −50.3 mV respectively) were found to be inversely linked to lactoferrin digestion rate. Moreover, the electrostatic binding of food grade iota-carrageenan onto lactoferrin nano-particles was found to yield highly charged particles (zeta = −69.2 mV) with low surface roughness and to enable a proportion of the lactoferrin to resist 1 h of simulated gastric digestion. Overall, these findings suggest that electrostatic biopolymer interactions may modulate protein digestion and possibly facilitate controlled protein delivery to the upper gastrointestinal tract or have implications to protein nutritional value.     

核桃粕膳食纤维提取、结构分析及粒度差异对其理化性质的影响

采用化学法从脱脂核桃粕中提取膳食纤维,研究5种不同粒度条件下（<40、40⁶0、60⁸0、80¹20、120¹60、>160目）核桃粕膳食纤维在持水力、膨胀性、吸油性、粘度、阳离子吸附力、葡萄糖阻滞力等理化性质方面的差异,以期为核桃粕膳食纤维的综合利用提供理论依据。结果显示,化学法提取的核桃粕膳食纤维得率为12.47%,膳食纤维含量为76.34%,蛋白质含量为5.41%;红外光谱扫描结果显示,核桃粕膳食纤维在3420 cm^-1处具有明显的纤维素特征吸收峰,表明核桃粕膳食纤维结构基本未受到破坏。不同粒度范围的核桃粕膳食纤维持水力、膨胀性和粘度均有显著差异。其中,粒度在120¹60目之间时,核桃粕膳食纤维持水力最好,为7.76 g·g^-1;粒度在80¹20目之间时,核桃粕膳食纤维膨胀值和粘度最大,分别为5.28 m L·g^-1、21.25 m Pa·s。核桃粕膳食纤维持油力（OAC值）随粒度减小呈增加趋势,当粒度>160目时核桃粕膳食纤维OAC值达到1.92 g·g^-1。此外,当核桃粕膳食纤维粒度为120¹60目时,葡萄糖阻滞力最强,粒度为80¹20目时,阳离子吸附能力最强。综合而言,核桃粕膳食纤维粒度在80¹60目之间时,具备最佳的理化特性。      

微波对膳食纤维结构和功能特性的影响

采用微波对甘薯渣、苹果渣、大豆渣中的膳食纤维进行改性,通过扫描电镜、X-射线衍射及热重分析,研究微波对3种膳食纤维结构的影响,并对比处理前后膳食纤维持水力、持油力、胆固醇吸附力、亚硝酸根离子吸附力的变化。结果表明：微波改性可以使膳食纤维的可及性边缘暴露,结晶度升高,热稳定性加强,且3种膳食纤维的功能特性均有不同程度改善,是一种优良的膳食纤维改性方法。此外,改性后3种膳食纤维中的可溶性纤维质量分数分别提高63.11%,4.51%,358.79%,与功能特性综合提高幅度并非正相关,改性后膳食纤维功能性质的提升是可溶性膳食纤维增加与不溶性膳食纤维可及性边缘的增加共同作用的结果。     

Preparation and properties of nano-SiO2-coated wool fibers

Nano-SiO₂-coated wool fibers were prepared by coating nano SiO₂ onto wool fibers pretreated by low-temperature plasma (LTP) irradiation. The morphologies and structures of coated wool fibers were characterized by scanning electron microscopy, transmission electron microscopy, and fourier transformation infrared spectrometry. The results show that after LTP irradiation, the surface structure of wool fibers was changed and new chemical bonds were formed; nano-SiO₂ combined well with the wool fibers and formed a functional layer on the surface of wool fibers. Compared with parent wool, the coated wool fibers had better thermal stability, breaking strength, elongation, and frictional property.     

Physicochemical and functional properties of flours from three Black gram (Phaseolus mungo L.) cultivars

Flours processed from three black gram cultivars (Mash1‐1, PU‐19 and T‐9) were studied for proximate composition, physicochemical and functional properties. Protein, fat, ash and crude fibre content varied significantly (P ≤ 0.05) from 24.5 – 28.4%, 1.1–1.4%, 2.7–3.3% and 2.7–3.4%, respectively, among the cultivars. Significant differences were also observed in other physicochemical properties. Pasting properties like peak viscosity, breakdown viscosity and setback viscosity were in the range of 2078.7–2473.0 cP, 644.0–863.7 cP and 588.3–804.0 cP, respectively. Textural profile analysis of flour gels displayed significant differences in hardness (13.0–18.9 g), gumminess (2.8–5.9 g), chewiness (2.0–5.7 g) and adhesiveness (21.0–40.9 g). Differential scanning calorimetry revealed starch gelatinisation from 63.5 to 75.6 °C and amylose lipid complex melting from 105.0 to 136.1 °C. Protein solubility profile in the pH range of 2–9 varied from 6.3 to 97.3%. Emulsifying activity index and Emulsifying stability index at pH 3, 5 and 7 varied correspondingly from 6.0 to 14.5 m² g^?1 and 18.8 to 64.9 min. Foaming capacity of 2% flour suspensions at pH 2, 4, 6, 8 and 10 varied significantly from 67.3 to 130% among the cultivars. Foam stability varied at different pH and was observed between 0 and 70.8% among the cultivars.     

In-vitro assessment of the effects of dietary fibers on microbial fermentation and communities from large intestinal digesta of pigs

Dietary fibers (oat β-glucan, flaxseed gum, and fenugreek gum) can be fermented to short chain fatty acids (SCFAs) in batch cultures by pig intestinal digesta. Lactate in the β-glucan-grown cultures had the highest level among SCFAs produced, whereas flaxseed or fenugreek gum-containing cultures generated a significant amount of acetate, propionate and butyrate over three subcultures tested (p < 0.05). Denaturing gradient gel electrophoresis (DGGE) analysis of 16S rRNA genes in the initial and subcultures revealed that types of fibers impacted pronouncedly on the bacterial community structure. Identified DGGE DNA bands were mainly affiliated with Bacteroidetes, and Firmicutes, in which numbers of butyrate-producing species were widely distributed. The fermentability of dietary fibers to SCFAs and their selection towards the bacterial communities suggest their potential application in promoting animal/human health.     

Effect of sterilisation on dietary fibre and physicochemical properties of onion by-products

Food industries are forced to develop productions without secondary residues. Therefore, there is a considerable emphasis on the recovery, recycling and upgrading of wastes. The possibility has been suggested for the conversion of onion waste into food ingredients, but with a stabilisation treatment being necessary. The objective of this work was to study the effect of sterilisation on fibre fractions, fibre composition and physicochemical properties of onion by-products to evaluate the use of sterilised onion by-products as a source of fibre.     

蔓越莓中膳食纤维的结构性质和功能性质研究

目的 考察蔓越莓中膳食纤维的结构性质和功能性质。方法 利用酶解法提取蔓越莓总膳食纤维、不溶性膳食纤维和可溶性膳食纤维, 并采用红外光谱和高效液相色谱测定其官能团结构和分子量, 采用质构仪和粘度计测定其凝胶性质和粘度, 同时对膳食纤维吸附亚硝酸根离子、交换阳离子、胆固醇、重金属和葡萄糖的能力进行研究。结果 总膳食纤维和不溶性膳食纤维的提取率较高, 分别为54.67%和38.70%, 膳食纤维具有凝胶和粘度的性质, 同时在功能上有吸附亚硝酸根离子, 交换阳离子, 吸收胆固醇, 重金属离子和葡萄糖的性能。结论 蔓越莓膳食纤维具有特殊的结构性质和很好的功能活性, 可以开发蔓越莓新功能食品。     

Mechanical and barrier properties of composite films based on rice flour and cellulose fibers

Rice flour is a low-cost starchy material, produced from rice that is broken during processing. Rice flour-based films have promising application on food packaging, because of their environmental appeal and low cost. Nevertheless, their mechanical and moisture barrier properties should be improved. The aim of this study was to develop biodegradable films based on rice flour and enhance their properties by reinforcing them with cellulose fibers. In this way, rice flour films with and without fibers were prepared by casting, with glycerol or sorbitol as plasticizer. Their physicochemical, microscopic and mechanical properties were studied. SEM analysis of films revealed compact structures. Films prepared with fibers presented lower water vapor permeabilities if compared with films without fibers. Films containing sorbitol were less permeable to water and more rigid. The incorporation of fibers reinforced mechanically the flour-based films, which presented higher tensile strength, but did not influence their deformation capacity. Therefore, preparing biodegradable films from rice flour is a new alternative of using this raw material. The use of cellulose fibers as reinforcing agent is a viable alternative to improve the properties of rice flour-based films, because they are biodegradable and available at low cost.     

聚酯纤维低聚物的产生原因、性质及防止

综述了近年来国内外对聚酯纤维低聚物问题的研究进展.分析了低聚物的产生原因和性质，结合传化公司的实际状况，指出了解决低聚物问题的方向。     

Effect of micronisation on dietary fibre content and hydration properties of lotus node powder fractions

Fibre‐rich fractions were obtained from nodes of lotus root and micronised by nine different ball‐milling treatments. The optimum milling conditions were screened out by comparing its effects on physicochemical and hydration properties of micro‐sized particles of lotus node powder fraction (LNPF). The micronisation by ball‐milling treatments was carried out at different speeds (200–400 r min^?1) and time (4–12 h). Ball‐milling treatments could effectively (P < 0.05) pulverise the LNPF particles to different micro‐sizes. As particle size decreased, a redistribution of fibre components from insoluble to soluble fractions was observed. Furthermore, micronisation treatments, especially 12 h at 300 r min^?1, could significantly (P < 0.05) increase the hydration characteristics, as well as impart lightness in colour to different extents. Our findings suggested that micronisation can improve physicochemical and hydration characteristics of the fibre components, which provide an opportunity to improve the utilisation and application of lotus node dietary fibre.     

Modification of insoluble dietary fibres in soya bean okara and their physicochemical properties

The changes in physicochemical and physiological properties of modified soluble dietary fibre (mSDF) in the okara using enzymatic [cellulase/substrates ratio of 2.0–6.0% (w/w) at 50 °C for 90–150 min], chemical [water bath of 1–3 h, water bath temperature of 50–90 °C, Na₂HPO₄ concentration of 0.1–0.9% and sample/reagent radio (S/R) of 1:40–1:60 (w/v)] and physical (homogenised once or twice under the optimal cellulase treatment condition) treatments were evaluated. The mSDF yield with chemical treatment (57.16%) was significantly (P < 0.05) higher than that of physical treatment [homogenisation once (16.54%) or twice (42.02%)] in combination with cellulase treatment. All treatments improved swelling capacity of mSDF and promoted bile acid‐ and cholesterol‐absorption capacity, but enzymatic and chemical treatments decreased the total reducing power of mSDF, except homogenisation‐cellulase treatment (141.74 μm  TE g^?1). Therefore, homogenisation‐cellulase treatment may be the appropriate method to improve the SDF proportion and ameliorate the functionality of okara.     

Effects of pretreatment methods on health-related functional properties of high dietary fibre powder from lime residues

Epidemiological studies have revealed that consumption of dietary fibre (DF) leads to many health benefits. Lime residues, which are by-products obtained after juice extraction, were used as raw material to produce DF powder. The residues are high in DF and possess a good balance between insoluble dietary fibre (IDF) and soluble dietary fibre (SDF). To process lime residues into value added products, some treatments prior to drying are required to reduce the bitterness, and this may affect the functional and nutritional properties of DF powder. This study investigated the effects of pretreatment methods of blanching, blanching-ethanol soaking (95% v/v for 30 min) and particle size reduction (38–450 μm) on selected health related functional and nutritional properties of DF from lime residues. The lime residues were dried at 60 °C before grinding. The functional and nutritional properties of interest included glucose adsorption capacity (GAC), glucose retardation index (GRI) and bile acid retardation index (BRI). The results show that DF powder prepared either by blanching or blanching followed by ethanol soaking prior to drying exhibited higher GRI and BRI. The pretreatments, however, did not affect the GAC. DF powder with smaller sizes also possessed higher GRI and BRI. The DF product with particle size in the range of 38–63 μm, and pretreated by blanching and ethanol soaking exhibited the highest GRI and BRI among all samples studied.     

Miniaturization of cellulose fibers and effect of addition on the mechanical and barrier properties of hydroxypropyl methylcellulose films

Cellulose fibers were miniaturized by microfluidics technology to decrease their size and incorporated in hydroxypropyl methylcellulose (HPMC) films to study the effect of addition of such fibers on the mechanical and barrier properties of HPMC films suitable for application in food packaging. The particle size of fibers and the mechanical properties, water vapor and oxygen permeabilities, total pore volume, and light and electron microscopy micrographs of films were analyzed. Incorporation of cellulose fibers in the films improved their mechanical and barrier properties significantly. This study is the first to investigate the use of microfluidics technology for the purpose of decreasing the size of cellulose fibers and the addition of reduced size microfibers to improve physical properties of HPMC films.