Seasonal variations of chemical composition in prickly pear (Opuntia ficus-indica (L.) miller)

The moisture, ash, free reducing sugar, starch, ether extractive, crude protein, amino acid and the heat energy contents of young and mature cladodes of Opuntia ficus-indica, with or without fruits, are described. The measurements were made in each of the following stages of development: vegetative growth (March), full vegetative development, and at the beginning of fructification (October). Independently of developmental stage (different cladode types) the highest values were reached always in young cladodes in the following months: moisture content in March and October; ash and free reducing sugars in March; starch and ether extractive in September and October; crude protein in March and July. Crude fibre was maximal in September and global heat energy in October. The nutritive and caloric value of cladodes are compared to other products used for livestock nutrition.     

秋香梨果醋醋酸发酵工艺优化及抗氧化活性研究

以秋香梨酒为原料,采用沪酿1.01醋酸菌,以总酸含量为指标,利用响应面法优化果醋醋酸发酵工艺,并评价果醋的抗氧化能力。结果表明:秋香梨果醋醋酸发酵的最佳工艺条件为醋酸菌接种量9.4%,发酵时间6d,发酵温度31℃,初始pH 4.5。此条件下得到的果醋色泽金黄,果香醇厚,其总酸含量为54.45g/L。秋香梨酒经醋酸菌发酵后,其DPPH自由基清除率、ABTS自由基清除率和Fe3+还原能力分别提高了21.17%,23.65%,30.23%,表明该果醋具有良好的抗氧化活性。     

Ethanol production by fermentation of fruits and cladodes of prickly pear cactus [Opuntia ficus-indica (L.) Miller]

Using prickly pear cladodes and fruits and different yeast strains of the genus Saccharomyces, both the chemical composition of the plant material and alcoholic fermentation were studied under controlled conditions. Before fermentation, fresh or previously dried cladodes were hydrolysed using cellulose or acid (HCl). The yield was determined by measurement of ethanol production by gas-liquid chromatography. Two conversion indices, representing either the percentage of reducing sugars or the energy converted into ethanol, were considered. Using fresh or dried cladodes without fruits, the best results were always obtained after performing both types of hydrolysis. The enzymic method gave the highest sugar yield. However, ethanol production was similar to that obtained by acid hydrolysis of fresh cladodes, and only slightly higher than that of previously dried cladodes. The potential ethanol production that could be obtained from prickly pear cultivation in various regions (arid, semi-arid and irrigated) is discussed.     

Relationship between changes in the total concentration of acetic acid bacteria and major volatile compounds during the acetic acid fermentation of white wine

BACKGROUND: In the scope of the wine vinegar production, this paper provides comprehensive information about the evolution of some volatile compounds during the biological acetification cycle. These data were compared with the acidity, cell concentration and ethanol concentration. Such information may allow a better understanding of the complex biological processes involved. RESULTS: The volatile compounds 2‐phenylethanol, diethyl succinate (diethyl butanedioate), meso‐2,3‐butanediol (meso‐butane‐2,3‐diol), levo‐2,3‐butanediol (levo‐butane‐2,3‐diol), methanol and ethyl acetate exhibited no significant changes between the starting wine and produced vinegar, whereas the rest [acetoin (3‐hydroxybutan‐2‐one) excepted] ethyl lactate (ethyl 2‐hydroxypropanoate), isoamyl alcohols (3‐methylbutan‐1‐ol and 2‐methylbutan‐1‐ol), isobutanol (2‐methylpropan‐1‐ol), 1‐propanol (propan‐1‐ol), and acetaldehyde were consumed in substantial amounts during the process. Additionally, their specific evolution patterns alongside bacterial cell concentrations, acidity and ethanol concentration are shown. CONCLUSION: Concentrations of acetic acid bacteria at the end of the acetification cycle were found to vary because of cell lysis, a result of the high acidity and low ethanol concentration of the medium. Variations were similar to those in some volatile compounds, which suggests their involvement in the metabolism of acetic bacteria. The results testify to the usefulness of this pioneering study and suggest that there should be interest in similar, more detailed studies for a better knowledge of the presence of certain volatile compounds and metabolic activity in cells effecting the acetification of wine. Copyright © 2010 Society of Chemical Industry     

Sherry wine vinegar: physicochemical changes during the acetification process

The quality of a wine vinegar is determined by the raw wine substrate and the acetification process employed in its production. Attempts to characterise vinegars have been based on these two features, along with variables such as total extract, glycerol, organic acids, volatile compounds and phenolic composition. When the final products are analysed, it is difficult to evaluate to what extent quality differences are due to the raw material or to differences in production methods, so it is necessary to determine the influence of each feature separately. The present work focuses on monitoring physicochemical changes during the acetification of sherry wine by submerged culture. ANOVA showed significant differences for ethanol, acetic and lactic acids and some volatile compounds (methanol, 1‐propanol, 2‐methyl‐1‐propanol, 2‐methyl‐1‐butanol, 3‐methyl‐1‐butanol, acetoin, acetaldehyde, ethyl acetate and ethyl lactate). However, no statistical changes were found for phenolic compounds during acetification. The phenolic composition of the final product was determined by the substrate employed. In addition, the influence of cycle duration on the chemical composition was studied; the only compound affected by this factor was 2‐methyl‐1‐butanol. © 2001 Society of Chemical Industry     

果胶酶对早酥梨醋发酵品质的影响研究

为提高早酥梨醋发酵品质,本实验研究了果胶酶对早酥梨汁主要成分的影响,优化了果胶酶酶解工艺,分析了酶解工艺对早酥梨汁酒精发酵、醋酸发酵及发酵产品品质的影响。结果表明,加入果胶酶后早酥梨汁的可溶性固形物、总酸、总糖、总酚、透光率均有所上升,当果胶酶添加量0.03%,酶解温度45℃,酶解时间2.5 h,pH值4.0时,早酥梨汁总糖含量可达到92.21±0.07 g/L, 比未酶解果汁提升29.27 %;酒精发酵、醋酸发酵速率较高,酒精转化率为70.7%,可滴定酸含量4.8±0.02 g/100mL;梨醋产品中7种主要有机酸含量无显著差距,17种氨基酸总量降低,必需氨基酸含量比例升高,与褐变相关的谷氨酸含量由16.55±0.01 μg/mL减少至12.02±0.02 μg/mL。与未酶解工艺比较,产品滋味协调、醇厚、澄清透明,品质较好。     

发酵条件对梨醋酿造过程中有机酸的影响

采用反相高效液相色谱分析了梨酒、梨醋中有机酸,研究了发酵条件对其有机酸的影响。研究结果表明:酿酒酵母在酒精发酵过程中可代谢梨汁中有机酸。与梨汁相比,梨酒中的草酸、奎宁酸含量下降,乳酸、琥珀酸含量上升。梨酒中乙酸、琥珀酸随着酒精发酵温度的升高而增加,而苹果酸、乳酸、奎宁酸则随着酒精发酵温度的升高而降低。醋酸菌具有代谢各种有机酸的功能,在醋酸发酵过程中均消耗柠檬酸,而产生和积累酒石酸。梨醋中酒石酸、奎宁酸、莽草酸、琥珀酸和乳酸随着醋酸发酵温度的升高而增加,苹果酸和草酸几乎不受发酵温度的影响。发酵方式影响醋酸菌对有机酸的代谢。      

Monitoring of seed composition of prickly pear (Opuntia ficus‐indica L) fruits during maturation period

Prickly pear fruit seeds were subjected to a range of chemical analyses during their 15 week maturation period. Seeds contained on average 71.5 g kg^?1 dry matter, 61.9 g kg^?1 crude oil, 9.4 g kg^?1 protein, 507.4 g kg^?1 crude fibre, 12.3 g kg^?1 ash and 409.0 g kg^?1 carbohydrate. The fatty acid composition of prickly pear seed oil consisted of 1.3–1.9 g kg^?1 myristic (14:0), 132.1–156.0 g kg^?1 palmitic (16:0), 14.4–18.5 g kg^?1 palmitoleic (16:1), 33.1–47.9 g kg^?1 stearic (18:0), 210.5–256.0 g kg^?1 oleic (18:1), 522.5–577.6 g kg^?1 linoleic (18:2), 2.9–9.7 g kg^?1 linolenic (18:3), 4.2–6.6 g kg^?1 arachidic (20:0) and 2.1–3.0 g kg^?1 behenic (22:0) acids, which is comparable with that of corn oil. No statistical difference in seed weight ratio was determined during the maturation period, whereas changes in the saturated fatty acids of the seed oil were observed. From this study it can be concluded that the seeds of prickly pear are suitable as animal feed. Copyright © 2003 Society of Chemical Industry     

The effects of fermentation on the thermostability of the yellow-orange pigments extracted from cactus pear (Opuntia ficus-indica)

 Cactus pear (Opuntia ficus-indica) juice with a total soluble solids content of 15.94 °Brix was fermented using the wine yeast Saccharomyces cerevisiae. A 94.54% conversion of fermentable sugar was achieved with an ethanol production of 55.3 ml/l. The pigment degradation was found to be 17% at the end of the time allowed for fermentation. However, the fermentation had actually ceased due to depletion of fermentable sugars after 12 h, a point at which only 9.4% pigment degradation was observed and there was no further total soluble solids degradation. The thermal stability of the yellow-orange pigment of the fermented juice was determined as a function of temperature at pH 5.0. The kinetic experiments were carried out at three different temperatures, 50, 70 and 90  °C. For a pseudo-first order thermal degradation rate the reaction rate constants were determined to be 0.0066, 0.0206 and 0.1244 min^–1 for temperatures of 50, 75 and 90  °C, respectively. The activation energy was calculated as 15.71 kcal mole^–1. The fermentation process did not affect the thermostability of the pigment extract. Received: 10 January 2000 / Revised version: 31 March 2000     

Effect of pH and temperature on the thermostability of prickly pear (Opuntia ficus-indica) yellow-orange pigments

The colour stability of the yellow-orange pigment (lambda max = 476 nm) of prickly pear (Opuntia ficus-indica) fruit was determined as a function of temperature and pH. The experiments were carried out at three different temperatures (50, 70 and 90 degrees C) with pigment solutions at pH values ranging from 2-7. The degree of pigment retention decreased with increasing temperature as a function of increasing thermal exposure time with least pigment degradation at pH 5. The reaction rate constants were determined as 0.0062, 0.0383 and 0.1102 min-1 for a thermal degradation reaction rate of pseudo-first order. The activation energy was calculated as 65.1 kJ.mol-1.     

岐山香醋醋酸发酵过程控制

文章论述了岐山香醋醋酸发酵过程中操作的技术要求及影响产品质量的几个环节和技改方案.     

航天香醋发酵工艺研究

采用搭载后的大曲,曲霉、乳酸菌等均有所增加。通过正交试验研究和模糊综合评价表明,在稀醪与酒精发酵时,活性干酵母添加量0．2％、航天大曲添加量1．2％、醋酸菌添加量0．7％,发酵温度32℃;固态发酵时以醋醅含水量60％、翻醅次数为10次、醅温控制在38℃,固态发酵15d,生产的航天香醋酸味柔和、丰厚、营养丰富,具有航天大曲特有香气。     

响应面法优化荞麦醋醋酸发酵工艺的研究

以荞麦为原料制备荞麦醋,以荞麦醋总酸含量为响应值,以拌醅酒精度、火醅接种量、醋醅水分含量为自变量,采用单因素试验和响应面试验优化荞麦醋醋酸发酵工艺条件。结果表明,荞麦醋醋酸发酵阶段最佳工艺条件为：拌醅酒精度4.50%vol,火醅接种量12%,醋醅水分含量65%,发酵时间9 d。在此优化条件下,荞麦醋总酸含量为4.86 g/100 mL。     

不同发酵方法酿造西瓜醋的挥发性成分分析

采用顶空固相微萃取-气质联用技术,对液态醋酸发酵（Liquid）和固态醋酸发酵（Solid）2种发酵方法酿造的西瓜醋的挥发性成分进行了测定与分析。根据Nist08数据库检索、定性和挥发性成分匹配度等方法,分别鉴定出42种和27种挥发性成分,分别占各自总挥发性成分的91.65%和92.31%。2种方法制备西瓜醋中,都含有醇类、醛类、酸类、酯类、烃类和呋喃类物质,醇类、醛类、酸类和酯类是西瓜醋中主要的挥发性成分。液态醋酸发酵中含有2种酮类物质,固态醋酸发酵中没有;液态醋酸发酵比固态醋酸发酵多15种挥发性成分,更有效的保留了西瓜中的挥发性成分。     

不同醋酸菌及发酵方式对柑橘果醋品质的影响

为了探讨不同醋酸菌对柑橘果醋品质的影响,该研究以柑橘为原料,采用沪酿1.01醋酸菌、AS1.41醋酸菌和许氏醋酸菌三种醋酸菌,通过一次发酵法和二次发酵法酿造六种柑橘果醋,并对这6种果醋的理化指标进行分析。结果表明,采用AS1.41醋酸菌、一次发酵法加工的果醋总多酚、总黄酮、蛋白质、单体酚、总氨基酸（TAA）、必需氨基酸（EAA）、非必需氨基酸（NAA）、呈味氨基酸含量分别为0.49 mg/mL、0.36 mg/mL、4.51 mg/mL、23.49 mg/L、1 830.10 mg/kg、420.80 mg/kg、1 409.30 mg/kg和1 822.10 mg/kg,均高于其他五种果醋,沪酿1.01和AS1.41醋酸菌、一次发酵法有机酸总含量较高,分别为11 786.03 mg/L和10 505.51 mg/L。综上所述,6种柑橘果醋中AS1.41醋酸菌、一次发酵法加工的柑橘果醋品质最好。     

Comparison of effects of prickly pear (Opuntia ficus indica sp) fruit,arabic gum,carrageenan, alginic acid,locust bean gum and citrus pectin on viscosity and in vitro digestibility of casein

The consumption of high levels of fibres can induce a decrease in both food digestibility and nutrient availability. Prickly pear is a pectin‐rich fruit and it is possible to use it to decrease plasma cholesterol levels. Its effect on food digestibility deserves attention. This effect was determined by using a mixture of a constant quantity of casein and an increasing quantity (10, 20, 25% of the casein) of prickly pear pulp, skin and seed. In parallel, the effect of similar mixtures of carrageenan, gum arabic, locust bean gum, alginic acid and citrus pectin with casein was also studied. The flow behaviour of the different mixtures was determined and their digestibilities were measured using an in vitro digestion cell device. The apparent viscosities of the mixtures with prickly pear components and gum arabic were similar. The nature and level of fibres in the diet modified nitrogen release in the in vitro digestion cell model. The pulp of the prickly pear decreased the digestibility of the casein‐based diet to a greater extent than the other soluble fibres, whatever the percentage used. The results suggest that the decrease in N release in the digestion cell model is due to the interaction of the fibres with the enzymes or casein rather than to the apparent viscosity of the mixtures. © 2000 Society of Chemical Industry     

葡萄糯米香醋发酵工艺的优化

该研究以葡萄和糯米为原料制备葡萄糯米香醋,以酒精度和感官评分为评价指标,采用正交试验设计优化其酒精发酵工艺条件;以总酸含量和感官评分为评价指标,优化其醋酸发酵工艺条件,并对该产品的挥发性成分、理化指标及感官品质进行分析。结果表明,最佳酒精发酵工艺条件为：葡萄与糯米质量比2∶1、初始糖度23%、葡萄酒高活性干酵母添加量0.22%、发酵温度28℃;最佳醋酸发酵工艺条件为：初始酒精度7%vol、醋酸菌（Acetobacter aceti）接种量5%、发酵温度30℃。在此优化条件下,葡萄糯米香醋共检出31种挥发性成分,其中醇类7种、醛类3种、酸类7种、酯类13种、苯类1种,总酸、总酯含量分别为4.70 g/100 m L、3.18 g/100 m L,葡萄糯米香醋呈红褐色、澄清透亮,口感醇厚、酸甜柔和,具有浓郁的果香和醋香。     

液态法生产葡萄醋过程的动态研究

以葡萄为原料，采用液态发酵法生产葡萄醋。研究了其生产工艺，分析了温度、通气量、酒精含量、接种量及pH值等对醋酸发酵过程的动态影响。结果表明：酒化过程中，糖度与酒度的变化呈负相关性，发酵度的变化情况呈抛物线形：醋化过程，采用前期低强度通气(1：0．8m^3／m^3／min)与后期高强度通气(1：2．0m^3／m^3／min)相结合，有利于醋酸发酵的快速进行。在一定的温度和通气条件下，影响醋酸发酵的主要因素为酒精含量、起始pH值和接种量，其最佳组合为酒精含量9％，起始pH值3．4，接种量12％。