Studies on the Characteristic Properties of Fermented,Sun-Dried Orange-Fleshed Sweet Potato Flour

Microbiological, functional, chemical and sensory properties of flours of two (2) cultivars of orange-fleshed sweet potato (centinnial and CIP 440293) being multiplied for distribution in South East and South-South Nigeria were investigated using standard techniques. The flours were observed to have good functional properties and high dry matter contents which were respectively 88.09 ± 0.00% and 86.0 ± 0.00%. The respective values for fat content (0.85 ± 0.00% and 1.75 ± 0.00 %), ash content (2.04 ± 0.00% and 2.40 ± 0.42%) and crude fibre content (2.90 ± 0.28% and 2.67 ± 0.00%) were low but the respective levels of carotenoids values (3.74 ± 0.00 and 5.28 ± 0.00 μg/g) were high indicating a promising source of pro-vitamin A. The sensory evaluation had no statistical difference among the parameters. The flours had high nutritive values with good functional and sensory properties. The microbial loads were within the acceptable limit of < 10⁵ recommended by ICMSF, making the flour samples microbiologically safe and with appropriate packaging, the shelf life could be extended under good storage conditions.     

高品质紫薯生全粉面条配方的工艺优化

为解决制作紫薯生全粉面条时常出现的断条率高、易糊汤、适口性不佳、颜色黯淡等问题,该研究以改善色泽和质构品质为目标对紫薯生全粉面条的配方工艺进行优化,分析阐明了柠檬酸、植酸钠、曲酸、茶多酚、β-糊精等护色剂以及卡拉胶、谷朊粉、魔芋葡甘露聚糖等改良剂在不同添加量下对面条色度、质构以及感官评分的影响,借助mixolab2混合实验仪等设备对比分析不同紫薯生全粉添加量下混合粉的粉质特性和糊化特性。结果表明：紫薯生全粉可影响蛋白网络弱化、淀粉糊化以及淀粉酶水解淀粉的速度,添加量超过10%会减弱面团筋度和耐揉性。紫薯生全粉面条适宜选用护色剂和改良剂分别为0.6%柠檬酸和0.6%魔芋葡甘露聚糖,感官评分较各自参照组分别提升13.56%和11.92%。在此基础上,通过4因素3水平正交实验确定了最优配方工艺为紫薯生全粉添加量8%,水添加量32%,柠檬酸添加量0.6%,魔芋葡甘露聚糖添加量0.6%,感官评分为85.48。本研究为后续高品质紫薯生全粉面条的工业化生产奠定基础。     

不同品种甘薯全粉基本特性研究

为了对不同甘薯全粉的加工适应性进行分析,实验对4 种甘薯全粉的基本成分及理化特性进行研究。结果表明：京553 持水性及凝胶性最好,徐薯23 持油性最强,京6 透光度最小;4 种甘薯全粉糊均为假塑性流体。综合所测指标,徐薯23 适合进行脱水薯类产品的开发;京6 直链淀粉含量较高,抗拉伸力,成型性好,能够增加产品的脆性和强力,京553 支链淀粉含量高,可用来提高面团的水合力,延缓烘烤食品变质。遗薯138 有优良的冻融稳定性,适于做冷冻食品的淀粉添加。     

Chemical, Physical and Sensory Attributes of Noodles with Added Sweetpotato and Soy Flour

Noodles were prepared with sweetpotato flour or puree and defatted soy flour (DSF) added to all-purpose wheat flour. These ingredients provided β-carotene for vitamin A and protein. Test samples were compared with control noodles. Combinations of sweetpotato and DSF increased protein, ash and total dietary fiber and decreased fat and carbohydrates. Sweetpotato contributed orange color and β-carotene, while DSF reduced lightness and added no β-carotene. Both ingredients increased cooking loss—10.4% from sweetpotato to 12.0% from sweetpotato and DSF combinations. Sweetpotato increased color acceptability with no change in flavor or overall acceptabilities. Sweetpotato decreased stickiness and DSF had no effect on acceptability.     

Textural Characteristics and Sensory Evaluation of Cooked Dry Chinese Noodles Based on Wheat-Sweet Potato Composite Flour

Effects of sweet potato flour (SPF) addition on dry Chinese noodles prepared from five wheat flours with variable quality (weak to very strong) were investigated. Color values expressed as L*, a* and b* were markedly affected by the levels of SPF. SPF addition reduced the springiness, cohesiveness, and resilience of the cooked noodles, but exerted varied effects on hardness and adhesiveness. Total scores of noodle samples prepared from composite flours decreased significantly with exception of very strong or strong flour. However, the reduction of total scores in wheat-SPF noodles was mainly due to decreasing of color and taste scores.     

常用淀粉对甘薯粉糊化特性的影响

利用Brabender粘度仪考察了几种常用淀粉对甘薯粉糊化特性的影响，认为马铃薯、甘薯淀粉使甘薯粉糊化温度降低，玉米、木薯淀粉则使其升高；甘薯、玉米淀粉使甘薯粉糊化时间延长。添加各种淀粉均可使甘薯粉的峰谷粘度提高；马铃薯、玉米淀粉还可大幅度提高其峰值粘度。但马铃薯淀粉粘度破损值大，玉米淀粉破损值小、峰谷粘度高。     

Physical, Chemical, Sensory and Microbiological Attributes of Sweet Potato Leather

A “vegetable leather,” possessing a supple, leathery texture, was prepared with sweet potato (SP) and other ingredients. Samples were analyzed at 0, 30, and 60 days storage. Texture, but not flavor or acceptance, was affected by experimental factors. Ingredients had only minor effects on composition. Mean values were: moisture, 5.9%; crude protein, 5.8%; crude fat, 4.9%; ash, 2.7%; crude fiber, 2.2%; and nitrogen-free extract, 84.8%. Dietary fiber was 4.1%. Color of the leather was orange; pH was 4.8; annd caloric content was 17.3 kJ per g. Water activity ranged from 0.48 for leather with SP and apple to 0.58 for leather with SP and without apple. Microbiological counts of samples were low.     

不同品种紫薯粉鲜湿面条的品质特性及主成分分析

为研究不同品种紫薯粉鲜湿面条品质特性的差异及紫薯粉的加工适宜性,选取10个品种紫薯作为研究对象,采用主成分分析法进行分析和综合评价。结果表明,不同品种紫薯鲜湿面条色泽特性、烹煮特性(熟断条率、烹煮损失率、膨胀率)、质构特性(硬度、黏聚性、回复性、内聚性、弹性、黏度、咀嚼性)、感官评分存在一定的差异性。通过主成分分析方法分析并提取了口感、烹煮、色泽、膨胀特性4项主成分,累积方差贡献率为87.990%。根据主成分综合评价法,总综合排名前4的品种分别是徐紫薯8号(综合得分0.854)、绵紫薯9号(综合得分0.607)、市售紫薯(综合得分0.118)、渝紫薯7号(综合得分0.114),进一步说明徐紫薯8号最适合用于紫薯粉鲜湿面条加工。本文为筛选适宜加工鲜湿面条的专用紫薯粉提供了依据。     

Chemical, Physical, and Sensory Properties of a Sweet Potato French-Fry Type Product During Frozen Storage

Chemical, physical, and sensory properties of a sweet potato Frenchfry type product were determined after 0, 3, 6, 9, and 12 months frozen storage. Analyses included measurements of dry matter, sugars, alcohol insoluble solids, carotene, vitamin C, color, texture and sensory panel scores for color, flavor and texture. Few changes were observed except for an appreciable loss (58%) in vitamin C and an apparent increase in carotene (27%). A partial drying treatment before freezing increased the rate of ascorbic acid loss. For the fried product, no appreciable storage-induced changes were noted in the sensory scores for color, flavor and texture thus indicating that the product had good stability in frozen storage.     

Potato Starch and Flour in Frankfurters: Effect on Chemical and Sensory Properties, and Total Plate Counts

Potato starch and flour were examined as possible constituents in frankfurter formulations. Frankfurters manufactured with 3% potato starch or 1.5% potato starch plus 1.5% potato flour in place of 3% wheat flour normally used as a binder, and stored at 4–5°C for 28 days did not differ significantly in percent shrink, water, protein, fat, ash or salt. Residual nitrite levels decreased during the storage period. Total plate counts reflect residual nitrite levels since the frankfurters (3% starch) with the lowest nitrite concentration also had the greatest number of bacteria (6.4 × 10⁶/g) on day 28. Frankfurters formulated with 1.5% potato starch plus 1.5% potato flour were rated more tender and more juicy than those made with 3% potato starch (P≤0.05 and P≤0.01) and 3% wheat flour (P≤0.01 and P≤0.01), respectively. Fresh potato starch and wheat flour franks did not differ from each other in either characteristic but after one week's storage the potato starch samples were rated more tender (P≤0.05) and more juicy (P≤0.01). Less force was required to shear the frankfurters formulated with 3% potato starch.     

板栗全粉添加对红薯粉物性及粉条品质的影响

为研究板栗全粉添加对红薯粉条品质的影响,优化板栗全粉红薯粉条制作方法。该试验以板栗全粉和红薯淀粉为原料,以膨胀势、溶解度、回生速率为混合粉评价指标,以粉条蒸煮特性和感官评分为粉条品质分析指标。试验结果表明：当板栗全粉的添加量分别为3%、6%、9%、12%、15%时,混合粉的膨胀系数均低于对照红薯粉组,溶解度均高于对照红薯粉组、回生速率与对照组差异不显著（p>0.05）;在试验组内,板栗全粉的添加对粉条的膨胀系数、烹煮损失率、断条率和感官评分均产生了显著影响（p<0.05）,板栗全粉的添加与粉条的品质呈负相关;在试验组内,当板栗全粉添加量在6%～9%时,能保证加工粉条的良好品质。     

Effect of Feathery Mottle Virus Infection on Sweet Potato Sensory Properties

Four sets of sweet potato clones obtained by meristem tip culture were used to investigate the effect of feathery mottle virus (FMV) infection on the appearance, sensory quality and chemical composition of the storage roots. This study, encompassing four generations, indicated that FMV infection had a slight effect on carbohydrate metabolism but no effect on the polyphenoloxidase-phenol system. Flavor and texture profile analyses indicated that for one clone, FMV-infected roots were more desirable when baked than healthy roots. Considering the study as a whole, FMV infection did not appear to adversely affect sweet potato sensory properties. Clones produced from the same parent by meristem tip culture might have different compositional and sensory properties.     

紫甘薯全粉流变学特性的研究

以紫甘薯全粉为原料,研究其在不同加工条件如剪切速度、加热、pH值、盐浓度、蔗糖浓度等影响下的流变学特性.结果表明:紫甘薯全粉溶液的黏度随加热时间的延长和溶液浓度的增加而增大;随温度的升高与剪切速率的增加而减小;pH值、盐浓度等对其黏度也有很大影响.     

Chemical Composition of Cell Wall Material from Sweet Potato Starch Residue

Cell wall material was isolated from the residue obtained after the extraction of sweet potato starch by treatment with the α-amylase. The wall material was fractionated by successive extraction with various reagents. The pectic substance was mainly composed of uronic acid (47.1%) residues and contained galactose as the predominant neutral sugar residues. The hemicellulosic fraction was further fractionated by precipitation with iodine in the presence of calcium chloride to give two fractions, a iodine precipitatable-iodine complex (HC-IP) and a supernatant solution (HC-IS). The HC-IS fraction had a higher glucose content (53.4%), whereas the HC-IP fraction had a high content of xylose residues (35.1%). The HC-IP fraction consisted mainly of xylan, as judged by the degradation with purified xylanase.     

Physicochemical Properties of Sweet Potato Flour and Starch as Affected by Blanching and Processing

The effects of blanching on physicochemical properties of flours and starches prepared from two varieties of sweet potatoes (Mun‐Kai and Negro) were studied and compared. The pasting temperature and peak viscosity of starches, respectively, were 74 and 80 °C and 381 and 433 RVU. The pasting temperature (74.0‐94.8 °C) of flours was greater than that of starch, depending on the variety and blanching process. However, the peak viscosity (ca. 103‐120 RVU) of flours was lower than that of the corresponding starches. Partial gelatinization of starch granules was observed as a result of a 1‐min blanching. Composition of starch and flour was found to affect swelling power and solubility. The starch content of starches, flours from unblanched sweet potato and flours from 1‐min blanched sweet potatoes were 97; 66.3 and 74.9; as well as 36.6 and 40.4%, respectively. Amylose content of flours and starches varied from 17.2‐20.8%.     

紫甘薯面条的加工工艺研究

采用单因素试验和正交试验相结合的方法,研究紫色甘薯面条的加工技术。结果显示,产品的最佳配方为:面粉80%、薯粉20%、食盐2%、卡拉胶1.25%、氧化淀粉3.25%。在此工艺条件下,产品断条率0%,烹煮损失率10.7%。     

Sensory Characterization of Sweet Corn Lines Differing in Physical and Chemical Composition.

Chemical, physical and sensory characteristics were determined in a population of 103 F₃ families derived from the cross between two sweet corn inbreds that differed in kernel properties associated with eating quality. Kernel characteristics correlated well with panel perception of sensory attributes. Chemical, physical and sensory properties were grouped into three factors: taste—including sweetness, starchiness, juiciness, and sucrose and starch concentrations; texture—crispness, tenderness, juiciness and cooked kernel tenderness; and aroma—sweet corn aroma, grassy aroma, grassy flavor and concentrations of an unknown volatile (V179). The relative importance in determining overall liking was taste 45.1, texture 30.5, and aroma 24.4%.     

魔芋胶对甘薯淀粉流变学特性及粉条品质的影响

研究多糖胶对淀粉糊化特性、老化特性、流变学特性及粉条食用品质的影响,为改善粉条品质提供理论指导。该文选择甘薯淀粉为原料,加入不同比例的魔芋胶,通过快速粘度仪(RVA)测定淀粉与魔芋胶复配体系粘度的变化来考察体系的糊化特性;用X衍射仪测定结晶度,评价体系的长期回生情况;通过流变仪考察魔芋胶对淀粉凝胶体系粘弹性的影响;最后评价魔芋胶对粉条食用品质的改善效果。结果表明:魔芋胶能够显著降低甘薯淀粉的糊化温度,提高粘度、崩解值和回生值,显著抑制淀粉的长期回生。甘薯淀粉/魔芋胶复配体系为屈服-假塑性流体,并且随着魔芋胶添加量的增加,屈服应力τ0、稠度系数K增加,流体指数n减小,复配体系有更好的粘弹性。甘薯淀粉和魔芋胶按质量比为8.5:1.5制备的粉条食用品质最佳。     

Effect of Curing on Sensory Properties and Carbohydrate Composition of Baked Sweet Potatoes

In a two-year study, the flavor and texture profiles and carbohydrate composition of cured, baked‘Jewels’sweet potatoes were compared to baked, uncured‘Jewels’sweet potatoes. Curing increased the rate of production of flavor notes and only slightly influenced development of “moist” mouthfeel. Given sufficient time after harvest, baked, cured roots were indistinguishable from baked, uncured roots. Carbohydrate content was not a sensitive indicator of post-harvest treatment since no statistically significant differences were detected between cured and uncured roots.