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.     

Cell wall modifications during cooking of potatoes and sweet potatoes

Sweet potato (Ipomoea batatas L) tissue, when cooked at 70 °C to activate β‐amylase and break down starch, takes on a distinctive firm, brittle texture and does not show the cell separation that occurs in, for example, cooked potato (Solanum tuberosum L). Similar cooking conditions increase firmness in other plants by activating pectin methyl esterase which de‐esterifies pectic polysaccharides and protects them from thermal depolymerisation. We therefore isolated cell walls from both potatoes and sweet potatoes cooked at 70 °C and 100 °C and determined the remaining degree of methyl esterification of their pectins. Pectins from both species were demethylated to a similar extent at 70 °C and 100 °C. Since cooking sweet potato at 100 °C induced cell separation and softening, it is concluded that β‐amylase is rapidly inactivated at that temperature and swollen starch distends and separates the cells, whereas the firm texture obtained by cooking that species at 70 °C is not the result of pectin demethylation but is caused by the breakdown of starch to oligomers that can escape from the cell. © 2000 Society of Chemical Industry     

Addition of waxy,low- or high-amylose rice starch differentially affects microstructure,water migration,texture and cooking quality of dried potato starch noodles

Potassium alum (PA) is commonly used as an improver for quality of potato starch noodles (PSN). However, PA poses health risks to consumers, thus making it imperative to seek substitutes for Al³⁺. In this study, effects of rice starch addition on quality of PSN were investigated. Scanning electron microscopy revealed that addition of low-amylose rice starch (LARS) or 40% waxy rice starch (WRS) enhanced structural development of PSN. Magnetic resonance imaging showed that the presence of LARS increased water retention in PSN. Addition of rice starch enhanced cooking quality of PSN by extending cooking time and significantly decreasing cooking loss (P < 0.05). Moreover, addition of LARS significantly (P < 0.05) increased tensile strength and hardness of PSN, whereas addition of WRS had the reverse effect. Mixing waxy potato starch with LARS at ratios of 4:1 or 3:2 is optimal for production of PSN.     

Comparative Investigation on Acid Hydrolysis of Sweet Potato Starches with Different Amylopectin Chain‐Length

The solubilization of starch from the new sweet potato cultivar “Quick Sweet” (QS) in 2.2 M aqueous HCl occurred at a much higher rate than that from normal sweet potato (NS). QS starch has an abnormal amylopectin chain‐length distribution with an unusually high percentage of short side‐chains. Two‐stage hydrolysis occurred in both cases. The apparent first‐order kinetic constants (k) were calculated for both stages of the hydrolytic process in both types of sweet potato starch. A more drastic difference between the investigated starches (k for QS and NS starches was 27.0×10^‐2 d^‐1 and 7.0×10^‐2 d^‐1, respectively) was observed for the first stage of the hydrolysis affecting the amorphous regions of starches whereas the rate for the second stage (the degradation of the crystalline part) for the starch from QS was only slightly higher. The role of the structural defectiveness of QS in decreasing the granular resistance to acid hydrolysis and increasing the absorptive properties of the granules for water molecules is discussed.     

In vitro availability of starch in heat‐treated potatoes as related to genotype,weight and storage time

The objective of the study was to determine the influence of potato variety, weight and storage time after lifting on the glycaemic index (GI) and resistant starch (RS) content predicted from measurement of the rate and extent of in vitro starch hydrolysis, respectively. The potatoes were either boiled, or boiled and subjected to different heat‐cycling conditions selected to promote retrogradation of amylose or amylopectin, respectively. The hydrolysis indices (HI) and predicted GIs of all 19 potato products were high and fell within narrow ranges of 122–144 and 118–138, respectively. No correlation between average weight of the potato tuber and HI was found. Furthermore, there was no difference in HI between potatoes stored for 1–3 or 8–10 months, nor between varieties of new potato and winter potato. However, the HI was significantly lowered by temperature cycling at conditions known to promote retrogradation of amylopectin (6 °C, 48 h) compared with 6 °C for 24 h followed by 70 °C for 24 h. RS content was already substantial in boiled potatoes, 4.5 g 100 g^?1 (starch basis), and could be increased further by temperature cycling, the highest yield obtained, 9.8 g 100 g^?1 (starch basis), following heat treatment at 6 °C for 24 h followed by 70 °C for 24 h; that is at conditions known to favour amylose retrogradation. Copyright © 2004 Society of Chemical Industry     

Some Properties of Starch Isolated from Radix Cynanchi bungei

The physicochemical and scanning electron micrograph characteristics of Radix Cynanchi bungei (RCb) starch were investigated. RCb starch presented an apparent amylose content of 20.1%, less than that of potato starch (23.6%), with a granule size ranging from 5 to 15 μm with round, spherical and polygonal shapes and B‐type X‐ray diffraction pattern. The RVA pasting properties of RCb starch were similar to those of potato starch, with pasting temperature of 60.8°C, lower than that of potato starch (64.3°C). The gelatinization parameters of RCb starch were found to be 55.9°C (T_o), 60.0°C (T_p), 66.6°C (T_C) and 13.2 J/g (ΔH) while those of potato starch were 58.9°C, 63.5°C, 68.6°C and 13.2 J/g. Both RCb and potato starch pastes behaved as high shear‐thinning liquids. RCb starch pastes had lower apparent viscosity than potato starch pastes at the same shear rate.     

Development and optimization of fish‐fortified instant noodles using response surface methodology

Proper and sensible formulation of ingredients in noodles facilitates its calorie cut down thus making it healthier. Fish being a source of cheap and quality protein can serve in the fortification of noodles. Hence, a study was done to formulate and develop fish noodles from Nemipterus japonicus. D‐optimal mixture experimental design with 15 runs was formulated to optimise the different levels of ingredients for noodles. Influence of different ingredients, viz. fish mince, wheat and refined wheat flour (maida) and potato starch, on the physical, cooking and sensory properties of fish noodles was evaluated. The protein content of noodles increased with increase in the fish mince incorporation. Water absorption capacity (WAC) was found to be directly related to the potato starch concentration. Positive correlation was observed between noodle protein content and cooking time. Desirability function scores revealed a noodle combination of 45% fish mince, 47% wheat: maida (1:1) mix and 8% potato starch as optimum.     

三种天然植物淀粉辅料对米粉丝品质特性的影响

以天然绿豆淀粉、玉米淀粉及马铃薯淀粉3种天然植物淀粉为原料,探讨其作为辅料添加对米粉丝蒸煮品质和质构特性的影响。结果表明,添加适量的绿豆淀粉、玉米淀粉或马铃薯淀粉可显著提高米粉丝的烹煮品质及质构特性。绿豆淀粉添加量在0.5~1.5%时加工的米粉丝具有较高的烹煮品质,其添加量在1%时可以显著提高米粉丝的质构特性;玉米淀粉的添加量为6%时米粉丝的烹煮品质较佳,其添加量在4~6%时可显著提高米粉丝的质构特性;马铃薯淀粉的添加量为2%时,米粉丝具有最高的烹煮品质,其添加量在2~3%时可使米粉丝的质构特性显著提高。综合考虑,当绿豆淀粉、玉米淀粉或马铃薯淀粉的添加量分别达到1%、6%和2%时能够显著改善米粉丝的蒸煮和质构品质特性。     

马铃薯淀粉添加量对真空滚揉调理鸡柳品质的影响

目的 探讨马铃薯淀粉结合真空滚揉腌制技术对调理鸡柳品质特性的影响。方法 通过测定调理鸡柳的出品率、蒸煮损失、水分含量、水分活度、色差、质构特征和剪切力等指标,探究不同马铃薯淀粉添加量（0.5、1.0、1.5、2.0和2.5%,w/w）对真空滚揉腌制调理鸡柳品质特性的影响。结果 随着马铃薯淀粉添加量的增加,调理鸡柳的出品率、嫩度、弹性、回复性、凝聚性、亮度值和红度值显著提高（P < 0.05）。然而,调理鸡柳的水分含量、水分活度、蒸煮损失、硬度则随着淀粉添加量的增加而显著下降（P < 0.05）,黄度值没有显著变化（P > 0.05）。结论 马铃薯淀粉的添加对真空滚揉腌制的调理鸡柳品质特性具有良好的促进作用,且以2.0%为最佳添加量。本研究为更高品质的调理鸡柳的工业生产提供技术支撑。     

不同加工处理时β-淀粉酶对紫甘薯淀粉及还原糖含量影响

根据林–贝双倒数作图法求得紫甘薯β–淀粉酶米氏常数为2.25×10–5mol/L,说明其具有较强水解淀粉能力。通过比较烘干法、晒干法、蒸煮法、烘烤法、微波加热法、油炸法六种不同加工方法对紫甘薯淀粉和还原糖含量影响可知,加工后淀粉含量下降1.02%~9.98%,还原糖含量增加2.60%~31.07%。对于紫甘薯不同加工方法,烘干处理比晒干更易于糖化,蒸煮与烘烤相近,但其糖化强度都不及烘晒处理;紫甘薯加工处理后,淀粉和还原糖含量变化幅度有较大差异,与其所含β–淀粉酶活性作用发挥呈有直接关系。     

Physicochemical Properties of Starch Isolated from Bracken (Pteridium aquilinim) Rhizome

Bracken (Pteridium aquilinum) is an important wild plant starch resource worldwide. In this work, starch was separated from bracken rhizome, and the physicochemical properties of this starch were systematically investigated and compared with 2 other common starches, that is, starches from waxy maize and potato. There were significant differences in shape, birefringence patterns, size distribution, and amylose content between bracken and the 2 other starches. X‐ray diffraction analysis revealed that bracken starch exhibited a typical C‐type crystalline structure. Bracken starch presented, respectively, lower and higher relative degree of crystallinity than waxy maize and potato starches. Ordered structures in particle surface differed among these 3 starches. The swelling power tendency of bracken starch in different temperature intervals was very similar to that of potato starch. The viscosity parameters during gelatinization were the lowest in waxy maize, followed by bracken and potato starches. The contents of 3 nutritional components, that is, rapidly digestible, slowly digestible, and resistant starches in native, gelatinized, and retrograded starch from bracken rhizome presented more similarities with potato starch than waxy maize starch. These finding indicated that physicochemical properties of bracken starch showed more similarities with potato starch than waxy maize starch.     

Effects of different crop starches on the cooking quality of Chinese dried noodles

To investigate the effects of seven starches made from different crop sources on noodle quality, Chinese dried noodles made from various reconstituted flours were prepared and analysed. Potato starch had better solubility and swelling power than the other starches, leading to higher water absorption, cooking loss and breakage ratio of the potato starch noodles. The correlation results unravelled that the cooking breakage ratio of noodles presented positive correlations with solubility, swelling power, peak viscosity (PV), trough viscosity (TV) and final viscosity (FV) values of starches. Besides, the adhesiveness of noodles showed a positive correlation with conclusion temperature (T_c) and setback viscosity (SV) values of starches. Moreover, the peak temperature (T_p) value of starches was negatively correlated with cooking loss; the granule size of starches had a positive correlation with noodles water absorption; and the peak time (PkT) value of starches represented positive relationships with noodles chewiness, shearing force and breaking strength.     

Starch Noodle Quality as Related to Potato Genotypes

Starch noodles were prepared using potato starch from 8 genotypes, mung bean starch, mung bean-potato starch blends, and sweet potato starch. The cooking quality of noodles from selected potato starches compared well with commercial starch noodles. Of the unblended potato starches, Mainechip exhibited cooking quality similar to commercial starch noodles with respect to cooking loss, cooked weight, and ?rmness. Appearance and texture of starch noodles from three genotypes (E55-35, Mainechip, and Shasta) were evaluated by a trained sensory panel. Noodles made from unblended potato starches had higher glossiness and transparency than those from other starches. Noodles from both un-blended and blended Mainechip starch had the highest press and elasticity.     

Digestibility of common native starches with reference to starch granule size,shape and surface features towards guidelines for starch-containing food products

Influence of diverse botanical sources (wheat, maize, waxy maize, cassava, potato, rice or waxy rice) on in vitro native starch digestibility has been investigated. Physicochemical properties (chemical composition, particles size and shape, surface features) of starch granules were determined with a view to explaining digestibility differences between samples. Rapidly digestible starch (RDS), slowly digestible starch (SDS) and resistant starch (RS) contents were measured according to Englyst method. Potato starch was shown to be composed of large rounded granules having smooth surfaces, which explains its slow enzymatic breakdown. Potato starch displayed the highest RS (86%) content and the lowest RDS content (9.9%). Since RS positively influences health and SDS may result in cell, tissue and/or organ damages, potato starch is an ideal starch nutrient. Conversely, waxy rice starch was rich in amylopectin and displayed small diameters and angular shapes, which are both known to facilitate enzymatic starch hydrolysis. It exhibited a near-zero RS content (0.9%) and a high RDS fraction (60%). According to this study, potato starch exhibited the best nutrient profile, followed up in this order by cassava, waxy maize, wheat, maize and waxy rice starches.     

添加淀粉对马铃薯米粉品质的影响

研究3种常用淀粉对马铃薯米粉品质的影响,为马铃薯米粉加工提供参考依据。分别将0%、5%、10%、15%、20%和25%的玉米、小麦和马铃薯淀粉添加到马铃薯全粉占比30%的米粉中,测定米粉蒸煮、色差、质构和拉伸性能指标的变化。结果:添加不同淀粉使得米粉的含水量显著减小(p<0.05);玉米、小麦以及5%~20%马铃薯淀粉可使米粉透射比显著增大(p<0.05);10%玉米淀粉能使碘蓝值显著增大(p<0.05);添加10%玉米、5%小麦以及5%~20%马铃薯淀粉,能使吐浆值显著减小(p<0.05);但3种淀粉对断条率影响均不显著。添加10%玉米、10%小麦和5%马铃薯淀粉能使米粉亮度L*显著减小(p<0.05),色度值a*和b*亦发生不同改变。5%~15%玉米淀粉可有效改善米粉硬度、峰值负载,但添加量达到20%时峰值负载形变量显著减小(p<0.05);小麦淀粉可改善弹性,添加10%~15%可有效改善硬度,15%和20%可改善峰值负载和咀嚼性;马铃薯淀粉可提高米粉硬度,但添加量达20%时米粉变得黏连。在实际生产中建议玉米和小麦淀粉添加量分别为5%和10%。     

马铃薯淀粉物化特性分析及其对马铃薯热干面品质影响

为研究马铃薯淀粉的物化特性,以马铃薯为试验原料并对其中淀粉进行提取,并探讨不同含量马铃薯淀粉对混粉物化特性以及生鲜马铃薯热干面和干制马铃薯热干面品质的影响。结果表明,马铃薯中淀粉含量为73.80%,马铃薯淀粉中直链淀粉含量为28.23%,支链淀粉含量为71.70%;马铃薯淀粉中快消化淀粉(RDS)、慢消化淀粉(SDS)和抗消化淀粉(RS)含量分别为20.29%、15.03%和64.68%。马铃薯淀粉添加量在60%～70%时,混粉的持水性、吸水膨胀性和粘度值较高;马铃薯淀粉含量为70%～80%时,能较好的改善生鲜马铃薯热干面的蒸煮特性和质构特性;马铃薯淀粉含量在70%时,干制马铃薯热干面的复水特性最好;随着马铃薯热干面中马铃薯淀粉含量的增加,干制热干面更易消化。综上所述,马铃薯淀粉的建议添加量为70%。     

Non-Starch Polysaccharides and in Vitro Starch Digestibility of Raw and Cooked Chick Peas

The effects of domestic and industrial cooking methods on the non-starch polysaccharides (NSP) content and in vitro starch digestibility of chick pea (variety “blanco lechoso”) have been studied. Total and soluble NSP increased, as did the slowly digestible starch (SDS), whereas the resistant starch (RS) fraction decreased after cooking, showing higher content in domestic than industrially cooked chick peas. The in vitro starch digestible rate index (SDRI) was similar in the cooked chick peas, as was the rapidly available glucose (RAG). Due to the low values of RAG, chick peas would give a slow post-prandial glycaemic response. Domestic cooked chick peas consumption would increase the intakes of RS in human diet, whereas the industrially cooked chick peas with lower content of RS would result in less flatulence problems.     

Short-chain fatty acid content and pH in caecum of rats fed various sources of starch

Caecal pH and contents of short-chain fatty acids (SCFA) were registered in rats fed three potential sources of resistant starch (RS); raw pea starch, raw potato starch, and an RS-enriched preparation obtained from wheat starch by autoclaving and enzymatic incubation. Small intestinal digestibility and delivery of RS to the hind-gut in the case of raw starches were determined by analysis of faecal starch in animals treated with antibiotics to prevent hind-gut fermentation. RS content in the RS-enriched preparation was determined as total starch remaining in an enzymatic gravimetric dietary fibre residue. The fermentability of RS was estimated from the faecal recovery of starch in normal animals with intact hind-gut microflora. Approximately 35 g per 100 g and 32 g per 100 g were RS in the case of raw potato starch and the RS-enriched preparation, respectively, versus only 1 g per 100 g in the case of raw pea starch. The caecal pH decreased with all test diets, being most significant with raw potato starch. SCFA production and faecal bulking were negligible with raw pea starch, whereas both raw potato starch and the RS-enriched preparation significantly increased these parameters. The fermentability of RS in raw potato starch and the RS-enriched preparation was similar, or about 60–70%. If calculated on basis of fermented amount, RS in raw potato starch was more potent in generating SCFA (49 μmol g^?1) than in the RS-enriched preparation (19 μmol g^?1). RS in raw potato starch also displayed the highest faecal bulking capacity. In fact, the faecal dry weight increased more than expected merely from delivery of RS. The relative proportion in caecal contents of acetic-, propionic- and butyric acid was 70, 17 and 8%, respectively, with no significant differences between the three sources of RS.     

Effect of Potato Starch Properties on Instant Noodle Quality in Wheat Flour and Potato Starch Blends

The properties of potato starch and their effect on the quality of Chinese‐style alkaline instant noodles made from wheat flour and potato starch blends were investigated. Starches were extracted from nine potato cultivars, and the phosphorus content of these starches was analyzed together with the median granule size and pasting and gelatinization properties. Instant noodles were manufactured using mixtures of wheat flour and these potato starches. A Rheoner instrument was used to evaluate three textural parameters, namely, the breaking force (BF), breaking energy (BE), and ratio of the breaking force to the breaking deformation (BF/BD), of instant noodles cooked by immersing into boiling water for 3 and 7 min. The phosphorus content, peak viscosity, and breakdown were significantly and positively correlated with the BF of the noodles cooked for 3 min and did not significantly correlate with that of those cooked for 7 min. Other quality parameters of potato starch did not affect the BF significantly. Other textural parameters of instant noodle quality, such as the BE and BF/BD, did not significantly correlate with any of the quality parameters of potato starch. The findings obtained with the use of wheat flour and potato starch blends suggest that phosphate, which is thought to enhance starch viscosity of potato starch, is important for making instant noodles with favorable texture in hardness.     

Extraction,Physicochemical and Compaction Properties of Tacca Starch — a Potential Pharmaceutical Excipient

Some physicochemical properties of tacca starch (Tacca leontopetaloides, Taccaceae) have been examined and the results compared to those of maize and potato starches. Tacca starch was found to have a higher amylose content than maize starch but a lower content than potato starch. The starch granules were small (average particle size 3.5 μm) relative to maize and potato starches and were predominantly polyhedral with edges. The gelatinisation characteristics except from the temperature were similar to those of maize starch but much higher than those of potato starch. Tacca starch had relatively higher swelling power and solubility than the other starches. Its features in the formation of compacts (tablets) were comparable to those of maize starch with tacca starch being more resistant to deformation.