Lactic acid production using waste generated from sweet potato processing

Organic waste generated from industrial sweet potato canning is estimated to be 30% of incoming raw material with significant residual carbohydrate content. The purpose of this study was to evaluate the potential of waste generated from sweet potato processing material to support the growth of lactic acid bacteria and the production of lactic acid. The waste was comprised of 16.5% solids consisting of 18.5% ash, 4.4% protein, 20.5% simple sugars and 19% soluble starch. Following a screening of three lactic acid bacteria strains, Lactobacillus rhamnosus was deemed the best candidate for lactic acid production. The potential of various dilutions of the enzyme‐hydrolysed waste, with and without pH control, as a fermentation substrate was evaluated. Lactic acid production was highest in hydrolysed waste (without dilution) at pH set point 5.0, yielding 10 g L^?1 in 72 h. Thus, lactic acid, a valuable organic compound, can be generated from sweet potato waste.     

Enzymatic Starch Hydrolysis of Extruded Potato Peels

Potato peels discarded by potato processors are a potential source of dietary fiber and starch. This starch may be hydrolyzed for fermentation to value-added products. Dried steam peels were extruded at 135°C and 22% feed moisture and digested with α-amylase and/or amyloglucosidase. Two barrel temperatures and feed moistures were also studied. Glucose was measured colorimetrically at O,1,2,4,8 and 24h of incubation. All peels treated with either no enzymes or α-amylase alone produced minimal glucose. Nonextruded peels digested with both enzymes produced more glucose than did those treated with amyloglucosidase alone. Complete digestion of starch occurred in extruded peels digested with amyloglucosidase, but not when α-amylase was used.     

Influence of konjac flour on foaming properties of milk protein concentrate and quality characteristics of gluten‐free cookie

The effects of konjac flour (KF) for modifying the foaming properties of milk protein concentrate (MPC) and characteristics of gluten‐free rice cookies were investigated. The three variables of konjac concentration (0.1–0.4%), pH (pH 5–9) and NaCl concentration (0.2–0.6 м) were studied. Both KF and pH had considerable effects on the foaming capacity (FC) and foaming stability (FS) of MPC. The NaCl had a negligible effect. Lowered FC and FS observed at pH 9 and pH 5 were increased with the increase in KF addition. Batter characteristics (flowability and consistency), cookie quality (moisture, yield, spread ratio, specific volume, hardness and colour) and sensory acceptance were evaluated in gluten‐free cookies with 0%, 0.25% and 0.4% KF. Konjac supplementation increased batter characteristics, yield, specific volume and hardness, but decreased lightness. Panellist acceptance, especially regarding texture and overall acceptability, increased in gluten‐free cookies with 0.4% KF. A higher purchasing decision was found for cookies with added KF.     

多种酶法处理提高马铃薯回生抗性淀粉制备率

以马铃薯淀粉为原料,以抗性淀粉制备产率为考察指标,研究α–淀粉酶、糖化酶和纤维素酶种类、酶加量、酶解时间、酶解温度、酶解pH、多种酶最佳配比及酶解顺序对RS3型抗性淀粉制备产率影响。固定条件:淀粉乳10%,高压温度120℃,高压时间30min,老化温度4℃,老化时间12h,糖化酶单独处理制备马铃薯回生抗性淀粉最佳酶解工艺条件为:糖化酶加量为1,200U/mL,酶解时间为60min,pH为5.0,酶解温度为55℃,制备产率达8.862%;纤维素酶单独处理制备马铃薯回生抗性淀粉最佳酶解工艺条件为:纤维素酶加量为40U/mL,酶解时间为45min,pH为5.0,酶解温度为35℃,制备产率达17.748%。α–淀粉酶、糖化酶和纤维素酶两两联合处理、三种酶共同处理均使马铃薯回生抗性淀粉制备产率降低;而纤维素酶处理可大大提高马铃薯回生抗性淀粉制备产率。RS3制备过程系为通过破坏纤维素等阻隔淀粉分子聚集的非淀粉物质提高制备产率,比将淀粉分子分解从颗粒结构中释放出以提高RS3制备产率更为有效。     

Enzymatische Prozesse bei der Verarbeitung von Kartoffeln

Enzymatic Processes in the Processing of Potatoes. The enzymatically convertable components of potatoes – starch, protein, fibres and pectins – are presented and especially the application of amylases (bacterial α-amylase, glucoamylase) in liquefaction and saccharification of pure potato starch, in direct enzymatic saccharification of potatoes and in the potato distillery is demonstrated. The use of bacterial α-amylase is also recommended for production of potato juice with dietetic effectiveness and in a quite new process for the conversion of wastes from convenient product plants (chips, pommes frites). The latter enables optimal results in pig-breeding or alternatively in obtaining of potable resp. power alcohol. Finally some other results in the treatment of potato pulp – waste material from potato starch manufacture – with pectinases, cellulases and amylases are given and the possibilities to modify potato protein described.     

两歧双歧杆菌1.1852的工业化发酵工艺

通过优化获得适合双歧杆菌工业化生产的,成本低廉的工艺条件。通过单因素试验,从番茄汁、低聚果糖、废糖蜜、马铃薯淀粉、玉米浆、豆饼粉6个因素中选出较优因素,并通过L9(3)4正交试验确定双歧杆菌发酵培养基的适宜配方及适宜发酵条件。结果表明:适宜的发酵培养基组成为番茄汁80ml/L、低聚果糖15g/L、废糖蜜20ml/L、玉米浆110mL/L、0.1%刃天青1mL/L、吐温-801mL/L、盐溶液40mL/L及L-半胱氨酸盐酸0.5g/L;适宜的培养条件为温度40℃、起始pH6.8、接种量3%,发酵时间32h。优化得到的培养基成本较低,发酵条件简单易控,适合双歧杆菌工业化生产。     

响应面法优化甘薯淀粉酶解工艺及动力学模型研究

研究甘薯淀粉的α-淀粉酶酶解工艺及动力学。以葡萄糖释放率为考察指标,研究酶解时间、酶量、淀粉浓度、p H值及酶解温度对α-淀粉酶酶解甘薯淀粉的影响,利用单因素和响应面法优化酶解工艺。通过Lineweaver-Burk和Wilkinson统计法求解米氏常数(Km)和最大反应速度(Vm),建立相应动力学模型。结果表明:α-淀粉酶酶解甘薯淀粉最优参数为:时间40 min,温度60℃,p H 5.0,酶量0.6 U/m L和淀粉质量浓度5 mg/m L,在此条件下,验证值为(50.676±0.294)%,n=5,RSD=0.519%。在p H 6.0,50℃条件下,活化能(Ea)=31.986 k J/mo L,Km=0.988 mg/m L,Vm=0.107 mg/(m L·min)。     

马铃薯淀粉凝胶形成及其品质影响因素研究进展

马铃薯淀粉黏度高、易糊化,淀粉糊稳定性及透明度高,被广泛应用于各类凝胶制品的加工中。温度、pH等环境因素以及盐类、多糖、蛋白质等食用成分对马铃薯淀粉的糊化特性及淀粉凝胶的回生特性、流变特性、微观结构等影响不同,进而影响马铃薯淀粉凝胶制品的品质。本文在分析马铃薯淀粉凝胶形成机制的基础上,综述了不同环境因素及食用成分对马铃薯淀粉凝胶品质特性的影响规律,揭示了不同食用成分与马铃薯淀粉分子之间的相互作用原理。旨在为高品质、高营养马铃薯淀粉凝胶及其制品的研究与工业化生产提供参考。     

Resistance of industrial mango peel waste to pectin degradation prior to by‐product drying

Susceptibility of industrial mango peel waste to pectin degradation during storage at ambient conditions (25 °C, 63% relative humidity) for up to 5 h before by‐product stabilisation by drying was explored. Depending on the interim storage period in the wet state, pectins were recovered from the dried peels by hot‐acid extraction. Most important, pectin degradation during the temporary storage of the wet peels was insignificant, as revealed by yields, composition, average molecular properties, and techno‐functional quality. Hardly acetylated (DAc 2.5–4.5%), rapid‐set high‐methoxyl pectins were obtained at starch‐corrected net yields of 14.1–15.6 g hg^?1. Irrelevant de‐esterification during peel storage in the wet state was confirmed by overall uniform setting temperatures. Arabinogalactans, uniformly indicated by high molar galactose/rhamnose ratios of 13.8–16.9 mol/mol and an arabinose percentage of 9.5–14.4 mol hmol^?1 of galactose residues, affected the galacturonide contents, intrinsic viscosities, and gel strengths throughout. The wet peels, derived from widespread manual peeling in mango canning, tolerated intermediate storage for 5 h, thus facilitating by‐product stabilisation on smaller scales.     

纤维素酶-压热法制备马铃薯抗性淀粉工艺参数优化

为了提高抗性淀粉的得率,并获得抗性淀粉制备方法的最佳工艺参数,该试验以马铃薯淀粉为原料,抗性淀粉得率为评价指标,采用纤维素酶-压热法制备马铃薯抗性淀粉。研究淀粉乳浓度、酶添加量、酶解时间、压热温度、压热时间5个因素对马铃薯抗性淀粉得率的影响,在单因素试验的基础上,通过正交试验优化得出马铃薯抗性淀粉的最佳制备工艺条件,即淀粉乳含量25%、淀粉乳pH 5.0、酶用量30 U/mL、酶解时间50 min、压热温度125 ℃、压热时间30 min、老化温度4 ℃、老化时间18 h,在此条件下抗性淀粉的得率为30.33%。     

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。     

采用无机陶瓷膜超滤甘薯淀粉生产废液中的糖蛋白的工艺研究

甘薯生产淀粉的废水中含有一种具有生物活性功能的糖蛋白,文中采用无机陶瓷膜超滤设备来提取甘薯生产淀粉废水中的糖蛋白。通过研究不同料液pH值、超滤操作时间、压力、温度、切线流速对渗透通量的影响,得出最佳的超滤工艺条件为pH=65,压力035MPa,温度20℃,切线流速u=2m/s,最终可将糖蛋白溶液浓缩83倍,糖蛋白的截留率为91%,糖蛋白得率为73%(粗糖蛋白中糖蛋白/鲜甘薯糖蛋白)。     

Recovery of lycopene from industrially derived tomato processing by-products by pulsed electric fields-assisted extraction

The influence of pulsed electric fields (PEF) pre-treatment at different field strength (E = 1–5 kV/cm) and energy input (W_T = 5–10 kJ/kg) on the recovery yield of lycopene in either acetone or ethyl lactate from industrial tomato peels residues, was investigated. The rate of lycopene extraction in both solvents decreased with time and was predicted rather satisfactorily (R² = 0.96–0.99) by the Peleg's model. Micrograph of tomato peels showed that PEF induced size reduction and separation between the plant cells likely due to pore formation and leakage of intracellular matter. Coherently, PEF treatment (5 kV/cm, 5 kJ/kg) significantly enhanced the extraction rate (27–37%), the lycopene yields (12–18%) and the antioxidant power (18.0–18.2%) in either acetone and ethyl lactate extracts, as compared with untreated samples. However, acetone gave the highest lycopene yield. HPLC analyses revealed that all-trans lycopene was the main carotenoid extracted and no degradation/isomerization phenomena occurred. The results obtained in this work suggest that the application of PEF prior to solid-liquid extraction with environmentally friendly solvents could represent a sustainable approach for the valorization of industrial tomato peels residues.Industrial relevanceIndustrial processing of tomatoes generates large amount of by-products, mainly peels, which represent a cheap and abundant source of natural carotenoids, especially lycopene. The recovery lycopene from tomato peels residues is a crucial step for use in a wide range of industrial applications in food, cosmetic and pharmaceutical sectors as natural pigment and antioxidant. PEF pre-treatment allows to intensify the extractability of lycopene from of tomato processing by-products using environmentally friendly solvents, thus adding new value to the tomato processing chain, improving economic performances and decreasing waste problems.     

The effect of glucose, starch, and pH on growth, enterotoxin and haemolysin production by strains of Bacillus cereus associated with food poisoning and non-gastrointestinal infection

Brain-Heart Infusion medium, modified by (a) 1.0% w/v glucose supplement, (b) 1.0% w/v soluble starch supplement, (c) pH adjustment to 8.8 or (d) pH adjustment to 5.0, was used to investigate the influence of glucose, starch and pH on growth, enterotoxin and haemolysin production by Bacillus cereus. The four test strains selected for comparison originated from episodes of emetic-syndrome food poisoning, diarrhoeal-syndrome food poisoning, traumatic wound infection and bovine mastitis, respectively. In the presence of either glucose or starch, growth of all strains was found to be near-optimum and accompanied by enhanced enterotoxin production. However, under the moderately acid and alkaline test conditions B. cereus strains exhibited varying degrees of growth inhibition and partial repression of enterotoxin and haemolysin production. In this respect the food-poisoning isolates proved to have greater resistance to adverse pH environments than did the non-gastrointestinal infection isolates.     

Isolation,identification and quantification of unsaturated fatty acids,amides, phenolic compounds and glycoalkaloids from potato peel

Eleven compounds were isolated from potato peels and identified. Their structures were determined by interpretation of UV, MS, 1D, and 2D NMR spectral data and by comparison with reported data. The main components of the potato peels were found to be chlorogenic acid and other phenolic compounds, accompanied by 2 glycoalkaloids, 3 low-molecular-weight amide compounds, and 2 unsaturated fatty acids, including an omega-3 fatty acid. The potato peels showed more potent radical scavenging activity than the flesh. The quantification of the 11 components indicated that the potato peels contained a higher amount of phenolic compounds than the flesh. These results suggest that peel waste from the industry of potato chips and fries may be a source of useful compounds for human health.     

同化淀粉酵母的筛选及其生物学性质的研究

菌株 Y960 1及 Y980 1是从 4株供试的同化淀粉酵母中挑选出的两株同化淀粉能力强的酵母菌株。在 3 0℃ ,p H5.5条件下 ,采用 2 %可溶性淀粉为唯一碳源的培养基摇瓶 2 4 h,酵母数每 ml分别达到 1 .5× 1 0 8个和 9× 1 0 7个 ;采用井岗霉素废渣培养基固态发酵 2 4 h,酵母数每 g分别达到 4 .1× 1 0 9个和 2 .7× 1 0 9个。对菌株 Y960 1及 Y980 1进行了生物学特性研究 ,表明菌株 Y960 1同化淀粉能力强 ,并对淀粉具有较强的酒精发酵能力 ,鉴定为酵母属糖化酵母的一个新种 ;菌株 Y980 1鉴定为异常汉逊酵母。这两株同化淀粉酵母在 4 0℃都能微弱生长 ,最适生长温度均为 3 0～ 3 4℃ ,最适生长 p H Y960 1株为 5.0～ 6.0 ,Y980 1株为 3 .5～6.0。     

抗消化性甘薯淀粉磷酸双酯制备工艺的优化

优化了三偏磷酸钠制备抗消化性甘薯淀粉磷酸双酯的工艺条件.采用响应面法Box-Behnken试验设计,分析了三偏磷酸钠、pH值、酯化温度以及酯化时间对甘薯淀粉磷酸双酯抗消化性能的影响.结果表明其最佳制备工艺为:三偏磷酸钠添加量3.6％(以甘薯淀粉计),pH 10.5,酯化反应温度50℃,酯化时间2.1h.在此条件下制备的甘薯淀粉磷酸双酯淀粉抗消化性为(58.73±0.04)％.经DSC和RVA扫描分析表明甘薯淀粉磷酸双酯仍具有与甘薯原淀粉相似的糊化特性.     

Enhanced production of α‐amylase from Bacillus subtilis subsp. spizizenii in solid state fermentation by response surface methodology and its evaluation in the hydrolysis of raw potato starch

This is an attempt to lower the cost of starch hydrolysis by the discovery of new generation α‐amylase. A natural isolate of Bacillus subtilis subsp. spizizenii was capable of producing appreciable amounts of raw potato starch digesting α‐amylase in solid state fermentation of wheat bran. The enzyme productivity has been substantially enhanced by supplementing various nutrients and statistically studying their interactions by response surface methodology. A central composite design for amylase production system elucidated a wheat bran‐based medium supplemented with soybean meal, threonine, and B‐complex vitamins predicting a yield of 521 391 U/g dry solids. The enzyme preparation could effectively digest 5–15% suspension of insoluble potato starch in 6 h revealing the dextrose equivalent of 32–44. The supplementation of a glucoamylase preparation, thereafter, brought about complete saccharification. The yield achieved in the statistically optimized amylase system may be one of the best to date and its capability in directly liquefying raw potato starch granules makes this study novel.     

Developments in Potato Production for the Starch Industry

From the price relationship between potatoes and maize gross margins can be calculated for various prices and yields of these two crops. From this can be concluded that in general potato production for starch can compete with maize for starch production at maize prices about 35 guilders. In the nine EC countries tuber yield per ha increased from 1962 to 1973 annually by almost 3%. In the Netherlands the yield per ha of starch from potatoes used for the starch industry increased from 1960 to 1975 annually also about by 3%. The average yield is now about 7 t/ha. It is estimated that under ideal conditions in the Netherlands the potential yield of starch would be 16 t/ha. Therefore much can be done to improve yield. In the period 1965–1973 in the Netherlands the total cost of potato production for starch increased by about 4% per year. In the last few years this increase was however almost 14% per year. Before 1973 rise in cost of production could be compensated for a large extend by the annual increase in yield per ha. That is not the case with a rise in cost by 14%.     

压热法制备甘薯抗性淀粉的工艺优化

利用压热法结合响应面分析法,优化甘薯抗性淀粉的制备工艺。以甘薯全粉为原料,研究全粉乳质量分数、pH、压热温度、压热时间、冷藏时间对甘薯抗性淀粉得率的影响。结果表明,响应面分析法得到甘薯抗性淀粉的最佳制备工艺条件为:全粉乳质量分数25.50%、pH7.30、压热温度120 ℃、压热时间31.20 min、冷藏时间24 h。在此条件下,甘薯抗性淀粉的得率为9.41%,与理论值较为接近,响应面模型与实际情况拟合良好,为获得甘薯抗性淀粉的工业化生产提供了参考。