Physicochemical,microbial, and sensory properties of nanopowdered eggshell-supplemented yogurt during storage

This study was carried out to investigate the possibility of adding nanopowdered eggshell (NPES) into yogurt to improve the functionality of yogurt and the effects of adding NPES on the physicochemical, microbial, and sensory properties of the products during storage. The pH and mean lactic acid bacteria counts of NPES-added (0.15–0.45%, wt/vol) yogurt ranged from 4.31 to 4.66 and from 6.56 × 10⁸ to 8.56 × 10⁸ cfu/mL, respectively, whereas these values ranged from 4.13 to 4.44 and 8.46 × 10⁸ to 1.39 × 10⁹, respectively, for the control samples during storage at 5°C for 16 d, which indicates a prolonged shelf-life with NPES-supplemented yogurt. Color analysis showed that the lightness (L*) and position between red and green (a*) values were not significantly influenced by the addition of NPES. However, the position between yellow and blue (b*) value significantly increased with the addition of the concentration (0.45%, wt/vol) of NPES at d 16 of storage. Sensory evaluation revealed that NPES-added yogurts showed a notably less sourness score and a higher astringency score than the control. An earthy flavor was higher in 0.45% NPES-supplemented yogurt compared with the control. Based on the results obtained from the current study, the concentration (0.15 to 0.30%, wt/vol) of NPES can be used to formulate NPES-supplemented yogurt without any significant adverse effects on the physicochemical, microbial, and sensory properties.     

Retrogradation of partially gelatinised potato starch prepared by ball milling

This study was performed to evaluate the effect of partial gelatinisation on the retrogradation of modified potato starch. The partially gelatinised starches with gelatinisation degree at mean levels of 22.47%, 49.18%, 76.80% and 86.19% were prepared by ball milling (0.5, 1.5, 3 and 10 h). The thermal properties and crystal structure of retrograded starch were examined during 21 days of refrigerated storage at 4 °C. Retrograded starch with high initial gelatinisation degree (86.19%) showed higher retrogradation enthalpy of 6.12 ± 0.18 J g^?1 and lower onset temperature of 45.41 ± 0.24 °C than sample with low gelatinisation degree (22.47%) where the results were 1.32 ± 0.18 J g^?1 and 54.05 ± 0.03 °C, respectively. During storage, two peaks in the X‐ray diffractograms for starch with high gelatinisation degree appeared and increased rapidly, while the peaks for starch with low gelatinisation degree increased slowly. These results suggest that a certain amount of remainder crystals presented in partially gelatinised starch impeded the retrogradation.     

Physicochemical properties of flour recovered from broken rice noodles during production

Flour recovered from broken rice noodles was evaluated by microscopy, X‐ray diffractometry, differential scanning calorimetry, in vitro starch digestibility, pasting and gel texture analyses. Rice noodle making processes destroyed the granular and crystalline structures of rice flour (RF), but the process‐induced recrystallised amylopectin and amylose‐lipid complexes were observed. Higher level of resistant starch in broken rice noodle flour (BRNF) was due to the retrograded amylose, which formed during noodle making. The absence of pasting temperature and low pasting viscosity of BRNF were distinct from those of RF, whereas gel textures of both flours were similar. BRNF‐added rice noodles showed lower hardness, but the other cooking and texture qualities were close to the one without BRNF. Up to 17% of BRNF could be incorporated into composite rice noodle making. This study thus provided an approach to the management and utilisation of food processing wastes.     

陈化前后大米的淀粉结构及理化性质分析

对比分析陈化前后6个不同品种大米淀粉结构与理化性质,结果表明,不同品种大米淀粉的直链淀粉含量、体积平均粒径（D[4,3]）、结晶度及糊化起始温度（To）、峰值温度（Tp）、终止温度（Tc）、热焓（ΔH）分别介于17.24%~22.69%、5.74~7.09 μm、16.45%~18.19%、64.77~73.03 ℃、71.73~81.13 ℃、77.17~87.40 ℃、12.62~18.44 J/g之间,陈化后大米淀粉的直链淀粉含量显著（p<0.05）上升,结晶度显著下降,陈化对淀粉晶型及短程有序性无明显影响;陈化对回生前后大米淀粉糊化特性均有明显影响,大米淀粉经回生处理后,To、Tp、Tc及ΔH明显下降;随着温度升高,大米淀粉溶解度与膨胀度明显上升,陈化降低了大米淀粉膨胀度、溶解度和透光率。大米淀粉的直链淀粉含量与其To、To＇（回生淀粉To）正相关;大米淀粉的D[4,3]与其To、To＇、透光率正相关;大米淀粉结晶度与其To、ΔH、ΔH＇（回生淀粉ΔH）正相关。该研究结果可为湖北稻米资源合理利用、陈米资源高效利用及产品开发提供理论依据。     

面粉不同粒度区间的理化特性研究

面粉粒度是评价面粉品质指标,对面粉及其制品的品质有重要影响。为研究粒度对面粉品质的具体影响,实验通过筛分方法,将4种商品粉进行粒度分级(140~160目,160~180目,180~200目,200目以上),研究商品面粉在不同粒度区间的分布情况,采用激光粒度仪扫描各区间面粉的粒度分布,测定各面粉区间的水分、灰分、破损淀粉含量、粗蛋白含量、面筋指数、湿面筋含量、干面筋含量,分析各区间面粉的成分变化及理化指标差异。研究表明,破损淀粉含量随粒度减小呈增加趋势,颗粒越小其破损淀粉含量越高;160~180目(96~80μm)和180~200目(80~75μm)区间的中间粒度面粉其理化性质与其它区间差异较大,通过方差分析发现不同粒度面粉的破损淀粉含量、粗蛋白含量、干面筋含量、湿面筋含量、面筋指数等指标均存在显著性差异。     

贻贝中微塑料检测的消解方法比较

目的 比较贻贝中微塑料(microplastics, MPs)检测常用的酸消解、碱消解、氧化消解和酶消解等方法,推荐适用于贝类中微塑料检测的通用型消解方式。方法 以常用的指示性双壳贝类贻贝作为研究对象,确定食品样品检测通用的消解条件。在这些条件下对聚苯乙烯(polystyrene, PS)、聚丙烯(polypropylene, PP)、聚碳酸酯(polycarbonate, PC)、聚乙烯(polyethylene, PE)、聚对苯二甲酸乙二醇酯(polyethylene terephthalate, PET)、聚酰胺6 (polyamide, PA6)和聚酰胺66 (polyamide, PA66) 7种微塑料进行消解,考察不同条件下微塑料粒子消解前后重量、红外光谱、粒径分布和形貌特征的变化。结果 采用不同的消解方式对不同的微塑料影响不同,其中重量受影响较大的是PA6和PA66,在硝酸-高氯酸混合溶液和高氯酸-双氧水混合溶液中完全溶解损失,PC和PET在氢氧化钾溶液中损失严重。通过结构表征, PE、PA6和PC的粒径增加, PC的形貌结构发生彻底改变。结论 对微塑料含量甚微的双壳贝类...     

Study on the physicochemical properties and in vitro digestibility of starch from yam with different drying methods

Four methods were applied to dry yam slices, and then, starches were isolated from dried yam slices. Starch isolated from fresh yam was as the study control, and physicochemical properties and in vitro digestibility of starches were studied. The results showed that the amylose content ranged from 12.62% to 28.25%, water‐binding capacity (WBC) from 111.67% to 262.88%, paste clarity from 2.1% to 6.23%, resistant starch (RS) from 66.60% to 88.49% and crystallinity from 11.27% to 25.52%. Compared with the control starch, hot air‐drying at 60 °C significantly decreased amylose content, paste clarity, RS and crystallinity, while increasing the WBC. Low levels of rapidly digestible starch and glucose and high RS levels were found in the starch from freeze‐drying yam. Digestibility of the starches was significantly correlated with amylose content, WBC, paste clarity and swelling power. The starch samples were divided into three groups by principal component analysis (PCA).     

兔皮胶原蛋白的微观结构及不同因素对其聚集特性的影响

以兔皮胶原蛋白为原料,通过紫外光谱(UV)、红外光谱(FTIR)和扫描电镜(SEM)对兔皮胶原蛋白的微观结构进行了初步研究,在该基础上进一步研究了温度、胶原蛋白浓度、pH值和离子强度对其聚集特性的影响。紫外光谱和红外光谱的峰型及对应波长均符合Ⅰ型胶原蛋白的特征,电镜扫描观察到兔皮胶原蛋白为不规则的致密片状膜,部分表面褶皱;聚集特性研究表明,胶原蛋白浓度与测定温度升高,胶原蛋白的聚集速度和聚集程度均增加;在酸性环境中,胶原蛋白聚集时间较长;pH由7增至8的过程中,胶原蛋白的聚集程度先增加后降低,在pH 7.2时,聚集程度和速度均最高;随着离子浓度的增加,聚集程度和聚集速度先增加后降低,在NaCl浓度为120mmol/L时聚集速度最快,且自组装程度最高。     

Starch Characterisation of Araucaria angustifolia and Araucaria araucana Seeds

Araucaria angustifolia and Araucaria araucana are conifers that cover different areas of South America. Their seeds have been consumed from prehistoric times until today in Brazil, Argentina and Chile. In this work, the starch of Araucaria angustifolia and Araucaria araucana seeds were analysed by light and environmental scanning electron microscopy, X‐ray diffraction, and differential scanning calorimetry. The starch granules of A. angustifolia and A. araucana were round or slightly oval, with a central hilum. Both starches gave X‐ray diffraction patterns compatible with the A‐type, with strong peaks at 15°, 17°, and 23°. The gelatinisation temperature of A. angustifolia starch (68.5°C) was higher than that of A. araucana (66.6°C), probably due to the higher amylose content of the former (22.4 % and 17.3 %, respectively). The thermograms of A. araucana starch presented a minor peak at about 71°C, which was attributed to the fact that the starch granules population of A. araucana was heterogeneous, with large and small granules, whereas A. angustifolia starch contained mainly large granules.     

Surface properties of walnut protein from AOT reverse micelles

The surface chemical composition and microstructure of walnut protein obtained through aqueous buffer and bis(2‐ethylhexyl) sodium sulfosuccinate (AOT) reverse micelles were determined by X‐ray photoelectron spectroscopy (XPS) and scanning electron microscopy (SEM). The surfaces were characterised by XPS to monitor surface composition. The different components of C 1s, N 1s and O 1s peaks were provided precisely. By comparison with walnut protein surface from aqueous buffer, XPS analysis revealed that the O atomic percentage of walnut protein powder surface from AOT reverse micelles was higher, but the C and N atomic percentages were lower. The N/C ratio of the walnut protein powders using two extraction methods was similar, while significant difference was obtained in the O/N. The obtained results indicated that the reverse micelles could affect the C, O and N components on the surface of walnut protein powder. Protein microstructure after reverse micelle treatment showed many crystals.     

罗汉参淀粉理化性质及降血糖活性研究

为研究罗汉参淀粉的理化性质和降血糖活性,该文对比研究罗汉参淀粉和玉米淀粉的抗性淀粉含量、透明度、膨润度、冻融性、黏度特性和持水性等理化指标,并采用扫描电镜对罗汉参淀粉颗粒进行表征分析;以链脲佐菌素诱导高血糖小鼠为模型,进行罗汉参淀粉的体内降血糖功能评价.研究结果表明,罗汉参淀粉的抗性淀粉含量为34.15％,糊化温度79...     

Hydrothermal Modifications of Tropical Tuber Starches. 1. Effect of Heat‐Moisture Treatment on the Physicochemical,Rheological and Gelatinization Characteristics

Cassava, sweet potato and arrowroot starches have been subjected to heat‐moisture treatment (HMT) under different conditions using a response surface design of the variables. A comparative study was performed on the pasting properties, swelling behaviour and the gelatinization properties of the modified starches and also on the rheological and textural properties of their pastes. X‐ray diffraction studies have shown that cassava starch exhibited a slight decrease in crystallinity, whereas sweet potato and arrowroot starches showed an increase in crystallinity after HMT at 120ºC for 14 h with 20% moisture. The swelling volume was reduced and the solubility was enhanced for all three starches after HMT, but both effects were more pronounced in the case of arrowroot starch. The decrease in paste clarity of the starch after HMT was higher in the case of cassava and sweet potato starches. Viscosity studies showed that the peak viscosity of all three starches decreased after HMT, but the paste stability increased as seen from the reduced breakdown ratio and setback viscosity. Studies on rheological properties have shown that storage and loss moduli were higher for the starches heat‐moisture treated at higher moisture and lower temperature levels than the corresponding native starches. Storage of the gel at ‐20ºC resulted in a significant increase in storage modulus for all the three starches. All the textural parameters of the gels were altered after the treatment which depended on the nature of the starch and also the treatment condition.     

Effects of pretreatment and drying methods on molecular structure,functional properties and thermal stability of fibre powder exhibiting colour from Centella asiatica L.

Effects of pretreatment and drying methods and particle size on characteristics of fibre powder from Centella asiatica L. leaves were investigated. Thermal stability of oil‐based colour solutions was also assessed. Steaming and combined steaming and alkaline soaking resulted in the powder with more greenness and higher chlorophylls contents, while combined steaming and acid soaking yielded dark yellow powder with lower chlorophylls contents. Chemical soaking led to the powder with decreased water holding capacity and solubility. Vacuum‐drying reduced chlorophylls degradation, hence retention of the greenness of the powder. Increased particle size resulted in decreased lightness of the powder, but in increased lightness of the solutions; water and oil holding capacities of the powder increased with the particle size. Fourier transform infrared (FTIR) spectra and X‐ray diffraction (XRD) patterns of the powder corresponded to its colour and functional property changes. Colour of the solutions changed only slightly upon heating at 80 and 180 °C for 1 h.     

Physicochemical and microbial properties of nanopowdered peanut sprout‐supplemented Caciocavallo‐like cheese during ripening

This study was carried out to investigate the physicochemical and microbial properties of nanopowdered peanut sprout‐supplemented Caciocavallo‐like cheese (NPSCC) during ripening at 14 °C for 6 weeks. The total phenol contents and lactic acid bacteria counts in NPSCC were significantly higher than those in the control, indicating that nanopowdered peanut sprout could potentially be used as a prebiotic and potential source of dietary antioxidants in the dairy products. Thiobarbituric acid values of the cheese were significantly decreased and the production of short‐chain free fatty was not significantly different when nanopowdered peanut sprout was added into the production of Caciocavallo‐like cheese.     

Physicochemical and functional properties of shell eggs following electron beam irradiation

Low dosages of electron beam irradiation (EBI) were applied to shell eggs to examine potential effects on physicochemical and functional properties. Prior to the assessment of physicochemical and functional properties, the antimicrobial efficacy of 2, 3 and 4 kGy dosages of EBI in shell eggs was established by the reduction of inoculated Listeria monocytogenes, Escherichia coli and Salmonella typhimurium to an undetectable level. Physicochemical changes to shell eggs receiving the same dosages of EBI were quantified by Haugh unit, free sulphhydryl groups, yolk index and lipid oxidation. Functional properties were assessed by foaming capacity, emulsifying capacity and gelling properties. A loss of thick albumen and a corresponding increase in free sulphhydryl groups in the albumen were observed after EBI, resulting in a loss of foam volume and gel hardness. Negligible changes in yolk index and lipid oxidation paralleled a retention of emulsifying capacity and gelling properties. EBI proved to be an effective method for controlling microbial growth in shell eggs without adversely affecting physicochemical and functional properties. © 2002 Society of Chemical Industry     

超微粉碎对苹果全粉物化性质的影响

以苹果为原料,经粗粉碎后超微粉碎不同时间(1、3、5、10、20、30 min),共得到苹果粗粉和6种不同粒径苹果全粉,通过测定其物化性质,并且利用激光粒度仪和扫描电子显微镜对不同的苹果全粉进行粒径测定和结构观察,探究不同时间的超微粉碎对苹果全粉物化性质及微观结构的影响。结果表明:超微粉碎后,粉体粒径逐渐减小,粒径分布越来越均匀。与粗粉碎苹果全粉相比,不同时间超微粉碎后苹果粉体的溶胀性、水溶性、持水力、阳离子交换能力均增大,容积密度减小(P0.05);随着超微粉碎时间的延长,持水力逐渐增大(P0.05),容积密度、溶胀性未发生显著变化(P0.05);各处理组间水溶性、阳离子交换能力先增大后未发生显著变化。本实验为苹果深加工提供了参考依据。     

Physicochemical and Functional Properties of Tetraploid and Hexaploid Waxy Wheat Starch

Waxy wheats possess unique starch functional properties that may be useful in specific end‐uses. To assess the physicochemical, thermal, and pasting properties, starches from seven waxy genotypes originating from two wheat classes, tetraploid durum and hexaploid hard red spring (HRS), were evaluated and compared with their counterpart non‐waxy wild types. The amylose content ranged from 2.3% to 2.6% in waxy durum lines, compared to 29.2% in normal durum control, and 2.1% to 2.4% in waxy HRS, compared with 26.0% in normal HRS control. Significant differences in the degree of crystallinity were observed between the waxy and control starches, despite similar A‐type X‐ray patterns, although differences between the two wheat classes were non‐significant. Both, control and waxy starches displayed an X‐ray peak corresponding to the amylose‐lipid complex, but the intensity of the peak was markedly lower in the waxy starches. The waxy durum starches exhibited the highest transition temperatures as measured by Differential Scanning Calorimetry (DSC), whereas, the enthalpy of gelatinization of most waxy genotypes was statistically higher than that of the controls. All waxy starches displayed high peak viscosity, high breakdown, and low setback profile as measured by the Rapid Visco Analyser (RVA). Texture analysis of RVA gels revealed significant differences between waxy and non‐waxy wheats, as well as between waxy tetraploid and hexaploid wheats, confirming that the nature and class of wheat starch would play a significant role when using waxy wheat blends in different wheat‐based products.     

Turmeric powder and starch: selected physical, physicochemical, and microstructural properties

Turmeric powder and its starch were characterized for physical, physicochemical, and microstructural characteristics. X-ray diffractogram indicated that turmeric starch to be of B type. Dried and cured-dried turmeric powder samples showed higher water-holding capacity (3.62 and 4.78 g/g, respectively) compared to isolated starch (1.07 g/g) at 30 °C. Non-Newtonian shear-thinning characteristics were observed with turmeric powder dispersion containing 10% (w/w) solids. A power law model fitted well to correlate the shear-rate and shear-stress data (r= 0.993 to 0.999, P≤ 0.01) for both samples. Apparent viscosities of isolated turmeric starch and cured-dried turmeric powder dispersion containing 10% (w/w) solids were 1.29 ± 0.03 and 7.57 ± 0.39 mPa s, respectively. Microstructure of starch particles showed a smooth flat outer surface. The approximate length and breadth of isolated elliptical starches were 25 and 10 μm while the thickness was about 5 μm. PRACTICAL APPLICATION: Isolation and characterization of starch from an unconventional source like turmeric rhizome indicate a potential application as a functional ingredient in foods and pharmaceutical industries including agglomerated products.     

A Study of Some Physicochemical Properties of High‐Crystalline Tapioca Starch

Tapioca starch was partially hydrolyzed in hydrochloric acid solution at room temperature for various lengths of time to obtain high‐crystalline starches. RVA viscoamylograms of acid‐modified starches demonstrated a very low viscosity as compared to that of native tapioca starch. The relative crystallinity of native and acid‐modified tapioca starches were measured by X‐ray diffraction ranging from 39.53% to 57.75%. The native and acid‐modified tapioca starches were compressed into tablets using various compression forces. The % relative crystallinity of starch increased with the increase in hydrolysis time and the crushing strength of the tablet was also increased in line with the crystallinity while the amylose content decreased when the crystallinity increased. These results suggested that the erosion of amylose might cause the rearrangement of starch structure into a new more tightly packed form, which provided the higher crushing strength for the tablets.