Physical and chemical characteristics of Asian sea bass bio-calcium powders as affected by ultrasonication treatment and drying method

The effects of ultrasonication and drying method on particle size and other product characteristics of bio-calcium powder from Asian sea bass (Lates calcarifer) backbone were investigated. Ultrasonication was performed at different amplitudes (60%, 70%, and 80%) for varying periods (15 and 30 min). Ultrasonication at higher amplitudes for a longer time reduced the powder particle size more effectively (p < .05), but had no impact on zeta potential (p > .05). The bio-calcium powder ultrasonicated at 70% amplitude for 15 min had the smallest particle size (3.38 µm) when compared to the control (28.85 µm). When the ultrasonicated bio-calcium was subjected to drying, freeze-drying produced powders with higher calcium solubility but lower whiteness than hot air (tray) drying. The results suggest that the ultrasonication is a potential suitable method to reduce the size of bio-calcium powders, while the drying method slightly affected the product characteristics. The bio-calcium powder could serve as a suitable functional ingredient for food fortification aimed at improving the calcium bioavailability. Particle size of bio-calcium powder from fishbone could affect the mouth feel and calcium solubility when used for food product fortification. This work showed that ultrasonication could be used to obtain up to 10-fold reduction in the particle size of fishbone bio-calcium powders, which promotes increased calcium solubility when subjected to simulated gastrointestinal tract digestion. Few differences in characteristics of the bio-calcium powder were observed for freeze-dried and hot air-dried samples. Thus, an economical, safe, and fast process can be implemented for the production of small particle size bio-calcium powder from fishbone.     

菊糖对马铃薯淀粉糊流变特性及体外消化的影响

为了研究菊糖对马铃薯淀粉糊流变特性及体外消化的影响,以马铃薯淀粉为原料,通过流变仪测试和体外酶解等方法测定菊糖-马铃薯淀粉共混体系的特性变化。流变仪测试结果表明:在试验的菊糖添加量范围内,菊糖-马铃薯淀粉共混糊的流变学特性均符合幂率模型,为假塑性流体;菊糖的添加在一定程度上降低了淀粉糊黏度,且随着添加量的增加,这一趋势加大。体外酶解结果表明:菊糖可以在一定程度上抑制马铃薯淀粉的水解速度及程度,且随着菊糖添加量的增加其抑制程度也相应增加;水解指数HI及预测血糖值e GI均随着菊糖添加量的增加而逐渐降低;在菊糖最大添加量时(菊糖与淀粉配比为1∶5),菊糖-淀粉共混体系的水解率、HI和e GI值分别由原淀粉的70%、57.87和71.48降至50%、42.74和63.17。研究结果提示适量的菊糖不仅可以改善马铃薯淀粉糊的流变性能,还可以降低其血糖指数。     

Effect of hydroxypropylation on physical and rheological properties of sweet potato starch

Sweet potato starches (SPS) were hydroxypropylated to evaluate the effect of molar substitution (MS, 0.042-0.153) on the rheological properties, thermal properties, freeze-thaw stability, paste clarity, and gel strength of hydroxypropylated sweet potato starches (HPSPS). The swelling power and solubility values of HPSPS were higher than those of native sweet potato starch (SPS) and increased with an increase in MS. The transition temperatures (T_o, T_p, and T_c), and enthalpy (ΔH) of gelatinization of HPSPS were lower than those of native SPS, and significantly decreased with an increase in MS.Rheological properties of HPSPS pastes were measured under the conditions of steady and dynamic shear. Their consistency index (K), apparent viscosity (η_a,100), Casson yield stress (σ_oc), complex viscosity (η*), and dynamic moduli (G′ and G″) values decreased with an increase in MS, while their flow behavior index (n) and tan δ (ratio of G″/G′) values increased. The dependence of apparent viscosity on temperature followed the Arrhenius model for all samples. The paste clarity of HPSPS paste was more pronounced with increasing MS of hydroxypropyl groups. The HPSPS gels showed lower gel strength and also better freeze-thaw stability with a significant decrease in syneresis (g/100 g) compared to native SPS.     

红薯/玉米淀粉共混物糊、流变及热力学性质研究

以不同质量比(0100,2575,5050,7525,1000)的红薯/玉米淀粉混合物为原料,用不同试验方法研究其糊化及流变学特征。布拉班德糊化结果表明:玉米淀粉成糊温度(77.7℃)高于红薯淀粉(73.2℃),红薯淀粉峰值黏度(513BU)大于玉米淀粉(281BU),混合淀粉的崩解值及回生值介于单一种类淀粉之间;动态频率扫描结果表明:玉米淀粉的储能模量约是红薯淀粉的4倍,混合淀粉的模量介于单一品种淀粉之间,均为弱凝胶;稳态流变曲线表明:被测样品符合Herschel-Bulkley模型,均为非牛顿型流体,相较于单一淀粉,红薯/玉米淀粉混合物触变性假塑性更强。剪切结构恢复力结果表明:红薯/玉米混合物淀粉凝胶抗剪切能力低于玉米淀粉。差示扫描量热(Differential scanning calorimetry,DSC)测定结果表明:玉米淀粉具有较高的热焓值,红薯/玉米混合淀粉热焓值降低。     

Gel texture and rheological properties of normal amylose and waxy potato starch blends with rice starches differing in amylose content

This study characterised the textural and rheological behaviour of blends of rice (waxy, low- and high-amylose) and potato (waxy and normal) starch. Blends of potato starch with rice starch in the ratios of 100:0, 80:20, 60:40, 40:60, 20:80 and 0:100 were tested. Addition of rice starch (except high-amylose rice starch) greatly increased the swelling of rice–potato starch mixtures. Addition of rice starch decreased gel firmness for most starch mixtures and increased gel adhesiveness for blends containing waxy potato starch. For rheological measurements, storage modulus was much higher than loss modulus of blends, indicating solid-like behaviour. Starch blends with 20%/40% proportion of rice starch showed a greater thickening effect, whereas with further increase in rice starch proportion, a pseudoplastic, shear-thinning behaviour was observed. This study may provide a basis to develop blends of potato and rice starch for potato noodle production without use of chemical additives.     

不同改性方法对红薯淀粉性质及粉条品质的影响研究

以3种不同处理方式(乳酸菌发酵、乳酸处理和湿热处理)对红薯淀粉进行改性,采用快速黏度测定仪(RVA)傅立叶红外光谱、电镜扫描仪和质构分析仪等仪器研究不同改性处理对红薯淀粉结构性质及粉条品质的影响。研究结果表明:与原淀粉相比,3种改性淀粉糊化特性的峰值黏度和衰减值有所降低,回生值都有不同程度的升高,淀粉分子结构的有序度也有不同程度的增加,除湿热处理淀粉的颗粒结构表面无明显变化,其他改性淀粉的颗粒结构表面有不同程度破坏。对3种改性淀粉与原淀粉粉条品质进行比较研究发现湿热处理淀粉所制粉条的断条率比原淀粉降低50%,硬度也由原来的2437g增加至3022g,粉条的拉伸强度由原来的80g增加到163.9g。     

Morphological,thermal, rheological and noodle‐making properties of potato and corn starch

A comparison between the morphological, thermal, rheological and noodle‐making properties of corn starch and potato starches separated from five different potato cultivars was made. The granule size and shape of all starches differed significantly. Potato starch granules were comparatively larger than corn starch granules, while the transition temperatures were found to be higher for corn starch. Consistency coefficients and flow behaviour indices measured by back extrusion were higher for potato starches than for corn starch. Stickiness of cooked starch pastes was observed to depend upon their consistency coefficient. The gels made from all potato starches showed higher gel strength than those from corn starch. The gel strength of starches from both corn and potato increased during refrigerated storage. The amylose content, swelling power, solubility and light transmittance values of potato starches were significantly higher than those of corn starch. Noodles made from potato starches had higher cooked weight and cooking loss than corn starch noodles. Texture profile analysis revealed that potato starch noodles also had higher hardness and cohesiveness than corn starch noodles. Hardness of cooked noodles from all starches increased and cohesiveness decreased during storage. Noodles made from starches of higher viscosity exhibited higher hardness and cohesiveness. Textural differences among cooked starch noodles appeared to be associated with morphological, thermal and rheological properties of corn starch and potato starches. © 2002 Society of Chemical Industry     

Effects of cross‐linking on the rheological and thermal properties of sweet potato starch

Sweet potato starches were modified with three different concentrations of phosphorus oxychloride (POCl₃) (0.01, 0.02, and 0.03%, based on dry weight of starch) as a cross‐linking agent. The effects of crosslinking on rheological and thermal properties of sweet potato starch (SPS) pastes were evaluated. Cross‐linking considerably reduced the swelling power, consistency index (K), apparent viscosity (η_a), and yield stress (σ_oc) values of SPS, which significantly decreased with increase in POCl₃ concentration. The gelatinization temperature (T_p) and enthalpy (ΔH) values of the cross‐linked SPS, which were determined using differential scanning calorimetry, were higher than those of native SPS. Storage modulus (G′), loss modulus (G″), and complex viscosity (η*) of the cross‐linked SPS pastes determined using small deformation oscillatory rheometry, were higher than native starch, and they also decreased with increase in POCl₃ concentration from 0.01 to 0.03%. The tan δ (ratio of G″/G′) values (0.15–0.19) of the cross‐linked SPS samples were much lower than that (0.37) of the native SPS, indicating that the elastic properties of the SPS pastes were strongly influenced by modifications from cross‐linking. Finally, Cox–Merz plots showed that η* was much higher than η_a for the cross‐linked SPS pastes.     

高静压处理对莲藕淀粉糊化、流变及质构特性的影响

为探究高静压对莲藕淀粉理化特性的影响,研究在不同压力、保压时间和淀粉乳浓度下莲藕淀粉糊化、流变及质构特性的变化趋势。结果表明,在200~500 MPa时莲藕淀粉的峰值黏度、谷黏度、终值黏度和成糊温度随压力增加而增大,而崩解值和回生值未发生明显改变;当压力达到600 MPa时,莲藕淀粉的峰值黏度和崩解值呈相反趋势,分别降低37.65%和96.49%,且在10%~20%浓度时,回生值平均下降43.34%,有效延缓莲藕淀粉的老化;随着保压时间的延长,峰值黏度和崩解值降低程度越明显,淀粉的抗剪切性及抗热性得到提高,处理30 min后,除最终黏度外,其它参数均无法获得;此外,经不同高静压处理后的莲藕淀粉流体指数n均小于1,仍为假塑性流体;且经200~500 MPa处理后,稠度系数K、G′和G″增加越显著,增稠效果明显;而当处理压力为600MPa时,二者开始下降并随着淀粉浓度降低和保压时间延长,下降趋势越明显;同时莲藕淀粉经不同高静压处理后,质构特性发生了一定的变化,特别是当增加淀粉浓度和减少保压时间时,莲藕淀粉的弹性、咀嚼性显著升高,硬度下降,但对内聚性无明显影响。     

Changes in rheological properties of hydroxypropyl potato starch pastes during freeze—thaw treatments. III. Effect of cooking conditions and concentration of the starch paste

The effects of different cooking conditions and concentrations on the freeze-thaw stability of hydroxypropyl potato starch (molar substitution 0·125) paste were investigated by dynamic rheological measurements and syneresis determination. The cooking conditions of the starch were chosen by taking the starch pastes at peak consistency (SP/Peak), at half breakdown consistency (SP/HB), after being held at 95°C for 15 min (SP/95°C) and after the whole pasting cycle (SP/25°C) in the Brabender Amylograph. The concentration effect was studied with the starch pastes after a whole pasting cycle at 35, 50 and 65 g kg^?1. Depending on cooking conditions and concentration, the rheological responses in changes of complex modulus (G*) and phase angle () of the starch pastes, with regard to the number of freeze-thaw cycles, differed considerably. This indicated that the starch pastes had undergone various structural changes during freeze-thaw treatments. With an increased extent of pasting, and with an increased starch concentration, the rheological responses indicative of the destabilisation process of the starch pastes were, in general, delayed. The number of freeze-thaw cycles required for the appearance of a peak in G*, related to the first syneresis, was one, two, five and six for SP/Peak, SP/HB, SP/95°C and SP/25°C, respectively. For the starch pastes at 35, 50 and 65 g kg^?1, it was four, six and seven cycles, respectively. Based on these rheological data, it was suggested that the amount of inter-mingled amylose and amylopectin in the dispersion of hydroxypropyl starch paste is the main controlling factor, which plays a critical role in the rheological response as well as in the syneresis.     

微波湿热处理对马铃薯抗性淀粉含量及性质的影响

在湿热条件下,采用不同微波条件对马铃薯淀粉进行处理,运用扫描电子显微镜、布拉本德粘度仪,对微波处理前后的物化性质进行了研究。结果表明,经微波辐射处理后,淀粉颗粒表面会出现小孔和凹坑;马铃薯淀粉中抗性淀粉和直链淀粉的含量、糊化转变温度及其范围、热糊稳定性和凝沉性得到提高;马铃薯淀粉的膨胀度、溶解度和粘度降低。      

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。     

Effect of temperature on the synthesis,composition and physical properties of potato starch

Potato tubers (cv Maris Piper) were grown at 10, 16, 20 and 25 °C in constant-environment chambers until maturity, whereupon the starches were extracted and subjected to rigorous chemical and physical analysis. The structure of the amylopectin molecules from the different starches post-debranching with isoamylase showed very little variation. The amylose and phosphorus content of the starches did show some variability while granule size tended to decrease as growth temperature was increased. There was, however, a marked increase in gelatinisation temperatures with a roughly constant enthalpy of gelatinisation as a function of growth temperature. The number of amylopectin double helices was determined by ¹³C CP/MAS-NMR and crystallinity by wide-angle X-ray diffraction and in common with the enthalpy of gelatinisation found to be almost constant. It is proposed that the differences in the gelatinisation temperatures reflect enhanced registration of the amylopectin double helices in crystallites which restricts hydration and hence elevates gelatinisation temperatures. This is probably associated with enhanced rigidity of amorphous regions. The consequence of these ordering effects is that swelling is restricted, even if there is no detectable order by DSC (post-T_c), because of steric hindrance to hydration exerted by the closer proximity/improved registration of the amylopectin chains. © 1999 Society of Chemical Industry     

Effect of temperature on the synthesis,composition and physical properties of potato microtuber starch

Potato microtubers (cv Maris Piper) were grown at 10, 16 and 24°C in total darkness for 28 days. Soluble and insoluble starch synthase, ADPglucose pyrophosphorylase, sucrose synthase and fructokinase were assayed in extracts of the microtubers and, in the case of soluble and insoluble starch synthase, activity was found to be particularly sensitive to increasing growth temperature. The starch content of the microtubers increased slightly with increasing growth temperature, but with little effect on the number of granules per microtuber and a small increase in the average granule size. The microtuber starch granules were much smaller than those found in commercial potato starch (c 8–9 μm modal diameter compared to c 21 μm). Although the amylose content of the microtuber starches tended to increase with increasing growth temperature, the phosphorus content was variable. Gel permeation chromatographic elution profiles of native and debranched microtuber and a commercial potato starch showed that no differences could be detected in either amylose or amylopectin molecular size, polydispersity or unit chain distribution of amylopectin (which contained two major unit chain fractions at DP 21 and 56). The onset, peak and conclusion temperatures of the DSC gelatinisation endotherm increased linearly as a function of growth temperature whilst the enthalpy of gelatinisation decreased. It is suggested that elevated temperature during starch biosynthesis facilitates ordering of amylopectin double helices into crystalline domains. © 1998 SCI.     

Effect of matrix and particle type on rheological,textural and structural properties of broccoli pasta and noodles

Durum wheat semolina (DWS) pasta and sweet potato starch (SPS) noodles were incorporated with different volume fractions and types of broccoli powder (up to 20% v/v). The incorporation of high volume fractions of broccoli powder produced in-house in SPS noodles increases the modulus of the dough and the stiffness and strength of the noodles as these broccoli particles can swell to up to 7.6 times their original volume. This effect is smaller when commercially available broccoli powder is used, as this powder can only swell 2.6 times. These results are confirmed by CLSM images. The incorporation of the two types of broccoli powder in DWS shows little effect on the rheology of this system. Since there is no difference between the water binding capacity of SPS and DWS, the small effects on rheology observed in the DWS system are due to the strong gluten network that can prevent the broccoli particles from swelling.     

Effect of peeling and unpeeling on yield,chemical structure,morphology and pasting properties of starch extracted from three diverse potato cultivars of Pakistan

The current study investigates the comparison and quality characteristics of starches isolated from potatoes using different processing methods from three commercial varieties: Lady Rosetta, Asterix and Challenger, for the first time in Pakistan. The analysis of variance revealed that starch yield significantly (P < 0.05) depended on total solids, peeling (12.7%, 12.0% and 12.0%) and unpeeling (15.0%, 14.0% and 14.0%) of potatoes compared to potato varieties for Lady Rosetta, Challenger and Asterix, respectively. Moreover, pasting properties, protein content, redness and yellowness were increased in those starches isolated without peeling while carbohydrates and lightness were increased in peeled potato starches. Furthermore, Fourier-transform infrared spectroscopy analysis revealed that protein (1200–1400 cm⁻¹) was present in starch extracted without peeling. Besides, scanning electron microscopy analysis revealed oval-shaped starch granules with no impurities in peeled potato starch. The findings suggest the suitability of peeling process for obtaining a high-quality pure starch.     

Effect of milk fat replacement by polyunsaturated fatty acids on the microbiological,rheological and sensorial properties of fermented milks

A modified milk (W3DD) where fat had been replaced by oils enriched in ω‐3 polyunsaturated fatty acids was used for the manufacture of a set‐type fermented product. In order to improve the organoleptic properties of the product, 30 g l^?1 whey protein concentrate (WPC) was added during the manufacturing process. Samples were fermented employing a commercial probiotic starter culture (ABT‐2), which contained Streptococcus thermophilus ST‐20Y, Lactobacillus acidophilus LA‐5 and Bifidobacterium lactis BB‐12. The acidification process was dependent on the WPC addition, which favoured the increase of viable counts, but fermentation was not influenced by the milk fat composition. The highest counts of the probiotic strains, L acidophilus LA‐5 (3.3 × 10⁵ cfu g^?1) and B lactis BB‐12 (5.5 × 10⁷ cfu g^?1), after 21 days of storage at 4 °C, were found in fermented products derived from W3DD supplemented with WPC. Addition of WPC also increased the firmness of the products and reduced syneresis. No apparent colour changes due to fat composition or WPC supplementation were observed in the products. Milk fat replacement by oils rich in ω‐3 polyunsaturated fatty acids had a negative influence on the product texture but did not affect the typical yoghurt flavour. These defects were overcome by the addition of 30 g l^?1 WPC, which improved the appearance, texture and general acceptability scores in the product. Copyright © 2004 Society of Chemical Industry     

Effects of raw potato starch and live weight on fat and plasma skatole,indole and androstenone levels measured by different methods in entire male pigs

A total of 96 entire male pigs were used to evaluate the effects of feeding raw potato starch (RPS) and live weight (LW; 90, 100 or 115 kg) on skatole, indole and androstenone levels in fat and plasma. Different methods to analyse the compounds were compared. Fat levels of skatole analysed by HPLC and colorimetric methods, and androstenone analysed by HPLC and ELISA, were highly correlated. However, androstenone values obtained by ELISA were overestimated. Feeding RPS reduced skatole levels in plasma and fat but did not affect indole levels. Androstenone levels in plasma measured by direct ELISA were not altered by diet, whereas the levels measured by ELISA with extraction were lower in the pigs fed RPS. Feeding RPS did not reduce androstenone levels in fat. Androstenone levels in fat were higher at 115 than at 90 kg, whereas skatole and indole levels were not affected by LW.     

Effect of different fibres on texture,rheological and sensory properties of acid casein processed cheese sauces

The objective of this study was the evaluation of different fibres (bamboo, acacia, potato or citrus) addition on texture, rheological and sensory properties of acid casein processed cheese sauces. Fibres used in production of sauces had an impact on the texture, viscosity, viscoelastic and sensory properties. The largest increase in viscosity was observed in products with addition of potato fibre, which have good water holding and adsorption capacity. Processed cheese sauce with the addition of citrus fibre was characterised by the highest values in general, and the increase of this feature in the tested samples was regular. Adhesiveness was the highest in products with 1% addition of every fibre. The lowest values of viscosity single shear, G′ and G″ moduli, among all tested, had sauces with acacia fibre. Moreover, they had the most thin liquid consistency, which was different from preferred one.