褐色乳酸菌饮料稳定体系的优化

为探究褐色乳酸菌饮料的体系稳定性,通过单因素和正交试验证明了葡萄糖添加量、褐变时间和发酵时间对乳酸菌饮料稳定性的影响较小;而基料添加量(蛋白质含量)、饮料pH和均质压力对稳定性的影响较大。获得褐色乳酸菌饮料最优稳定体系参数为：葡萄糖添加量80 g,褐变时间2 h,发酵时间72 h,基料添加量200 g,饮料pH 3.7,均质压力200 MPa。研究结果不仅优化了褐色乳酸菌饮料的制作工艺,而且降低了稳定剂的添加量,降低了生产成本。     

一种无稳定剂褐色乳酸菌饮料的研究

常规乳酸菌饮料通常使用果胶、羧甲基纤维素钠等稳定剂维持产品的稳定性,否则产品在货架期内容易出现蛋白质沉淀、分层等不稳定现象。本文中,笔者通过单因素和正交试验,以粒径为指标,研究了蛋白质含量、发酵时间和葡萄糖含量对乳酸菌饮料稳定性的影响。研究结果表明:当蛋白质质量分数为0.9%、发酵时间为60 h、葡萄糖添加量为8%时,乳酸菌饮品稳定性最佳。     

以青砖茶为原料的果茶饮料制备

以青砖茶、新鲜苹果汁、西瓜汁和菠萝汁为主要原料进行果茶饮料的研制,采用单因素试验及正交分析试验对果茶饮料的配方进行工艺优化,以感官评价和吸光值为评定指标,确定果茶饮料的最佳配方。结果表明,体积比分别为8∶2的茶汤与苹果汁的混合汁、5∶5的茶汤与西瓜汁的混合汁和3∶7的茶汤与菠萝汁的混合汁混匀调配出的茶饮料的口感最佳,色泽清透,且香气较佳。本研究为黑茶果茶饮料的研 制提供了理论依据。     

苦荞麦菠萝复合饮料的工艺研究

以苦荞麦和菠萝为原料,研究了苦荞麦的浸提工艺和苦荞麦菠萝复合饮料的工艺,得出了苦荞麦的最佳浸提工艺:浸提时间30 min,浸提温度90℃,料水比为1:15;苦荞麦菠萝复合饮料的最佳工艺:苦荞麦浸提液和菠萝汁比值为1:1,白砂糖的添加量为4%,卡拉胶的添加量为0.2%,在最佳工艺下苦荞麦菠萝复合饮料色泽鲜亮、透明呈淡黄色,具有苦荞麦和菠萝的香气,口感柔和浓郁,汁液均匀,无沉淀,透明度高。     

火龙果汁发酵饮品的研制

火龙果不但营养丰富而且具有一定的保健功能。本试验以新鲜的红皮白肉型火龙果果实的榨汁为原料,分别对发酵工艺条件、蔗糖添加量、柠檬酸用量、稳定剂用量等条件进行了研究,通过单因素试验和正交试验,得到火龙果汁发酵饮料的最佳工艺配方。采用该工艺配方制备的发酵饮料澄清透明,具有清新的果香和淡淡的醇香,酸甜可口,口感顺滑。     

纺织精练中碱性果胶酶稳定性的改进研究

从碱性果胶酶在纺织清洁生产中的应用条件出发,在60℃和pH 9.1左右,系统研究了不同稳定剂对提高碱性果胶酶的稳定性的影响。由此,得到了对酶稳定性作用较突出的添加剂以及复合稳定剂,较佳配方为乙酸钠6%(m/v)、MgCl2.2H2O 2%(m/v)。结果表明,添加稳定剂后的碱性果胶酶在棉织物精练中的应用特性得到了提高,达到了棉织物精练的需要。     

紫胡萝卜番茄复合果蔬汁饮料的研制

以新鲜紫胡萝卜和番茄为原料,研制紫胡萝卜番茄复合果蔬汁饮料,并对紫胡萝卜浆、番茄浆和糖酸的用量、稳定剂种类和添加剂用量进行优化。结果表明：产品最佳配方为总果浆含量30%,紫胡萝卜浆：番茄浆的体积比为2∶1,白砂糖添加量为10%,柠檬酸添加量为0.1%;稳定剂最优组合为黄原胶添加量为0.06%,羧甲基纤维素钠添加量为0.15%,果胶添加量为0.04%。所得产品具有紫胡萝卜和番茄所特有的香气,口感细腻,组织状态良好。     

番石榴原浆及饮料生产工艺研究(简报)

本试验以3个品种番石榴为原料、酶处理为关键技术,研究番石榴原浆工业化生产工艺,确定了果胶酶适宜的添加量、pH值、反应温度及辅剂和稳定剂,使出汁率提高13．8％;确定了番石榴饮料的最佳配方,果汁饮料稳定时间迭156d。     

莲心保健饮料的研制

莲心是具有多种保健功能的天然产物,很有研究和开发的价值。本义对利用莲心生产保健饮料进行了研究。采用煎煮后捣碎离心、过滤的方法提取的莲心汁在浓度、色泽及稳定性方面综合效果最佳。在煎煮过程中添加适量的柠檬酸及异抗坏血酸钠后,能较有效地控制所得莲心汁的褐变速度,达到护色目的。加入PVPP或聚酰胺可增加莲心汁的稳定性。用提取的莲心汁可与其它不同的组分配成口感和风味各异的莲心饮料。     

火麻仁复合蛋白饮料的研制

以全脂乳粉、火麻仁为原料,探讨了火麻仁复合蛋白饮料的制备工艺条件。通过正交试验研究了火麻仁复合蛋白饮料产品配方及乳化稳定剂的复配方案。结果表明：火麻仁复合蛋白饮料最佳配方为全脂乳粉2.0%、火麻仁3.0%、核桃仁1.0%、白砂糖6.0%;火麻仁复合蛋白饮料最佳稳定剂为单,双甘油脂肪酸酯0.04%、蔗糖脂肪酸酯0.05%、山梨醇酐单硬脂酸酯0.02%、结冷胶0.03%。     

Carotenoid production by Xanthophyllomyces dendrorhous: use of pineapple juice as a production medium

Aims:  To select a carotenoid-hyperproducing mutant and to formulate pineapple juice as a carotenoid production medium.
Methods and Results:  Yeast strain of Xanthophyllomyces dendrorhous mutant GM 807 (derived from gamma irradiation) and the mutant n78 (from neutron irradiation) were selected based on higher carotenoid production in diluted pineapple juice as a medium. The selected strain was evaluated under various concentrations of pineapple juice. The results obtained in the study demonstrate that the mutant GM 807 enhanced production by 65·8% when using pineapple juice as medium at 10% dilution in place of yeast malt medium.
Conclusion:  Pineapple juice could be used as a sole medium for carotenoid production.
Significance and Impact of the Study:  Our results provide useful information for the design of production media for carotenoids to be used in various applications.     

Inhibitory effects of fruit juices on cytochrome P450 2C9 activity in vitro

There is limited information on the effect of fruits on human cytochrome P450 (CYP) 2C9 activity. The objective of this study was to determine the effect of fruit juice on CYP2C9-mediated drug metabolism. Nine citrus fruits and eight tropical fruits were chosen. We investigated effects of the fruits on diclofenac 4'-hydroxylation and tolbutamide hydroxylation by human liver microsomes. Among the fruits, pineapple juice showed potent inhibition of CYP2C9 activity. The addition of 25 microl (5.0% v/v) of pineapple juice resulted in almost complete inhibition. Next we examined the inhibitory effect of bromelain, a cysteine protease in pineapple. Bromelain also strongly inhibited CYP2C9 activity. In addition, E-64, a cysteine protease inhibitor, almost entirely blocked inhibition by pineapple juice and bromelain. Thus we found that pineapple juice was a potent inhibitor of CYP2C9, and that the inhibitory effect might be due to the bromelain contained in pineapple.     

Evaluation of baits for trapping of Neotropical flower chafer beetles (Coleoptera: Scarabaeoidea: Cetoniinae)

The lack of a standardized protocol to efficiently capture flower chafer beetles (Coleoptera: Scarabaeoidea: Cetoniinae) in the wild limits studies regarding the ecology of the group, as well as systematic collections seeking species surveys for taxonomic studies, especially in the Neotropical region. We investigate the efficiency of different baits to capture flower chafer beetles in the Brazilian Cerrado: (i) banana; (ii) banana + sugarcane juice; (iii) pineapple; (iv) pineapple + sugarcane juice; (v) sugarcane juice; or (vi) water (control). From January to December 2014, we sampled these beetles using a typical aerial fruit‐baited trap, every 15 days in ten sites of Brazilian Cerrado, in Aquidauana, Mato Grosso do Sul, Brazil. Traps baited with banana + sugarcane juice, pineapple + sugarcane juice and sugarcane juice alone sampled the greatest species richness and abundance of flower chafer beetles when compared to the other baits used. Our results indicated the importance of sugarcane juice, either used in isolation or as a coadjutant in the fermentation process of the tested fruits for efficient sampling of flower chafer beetle biodiversity. Finally, studies that investigate the addition of other substances in the fermentation process of the fruits, as well as the attractiveness of other native or exotic fruits that are widely distributed in the Neotropical region, can advance our knowledge of sampling of these beetles.     

Two low-cost food attractants for capturing Toxotrypana curvicauda (Diptera: Tephritidae) in the field

Adults of the papaya fruit fly, Toxotrypana curvicauda Gerstaecker, living in wild vegetation in Yautepec, Morelos, Mexico, were captured using McPhail traps baited with pineapple juice or brown sugar. Maximum capture peaks occurred during August and November in the afternoon. Baits were most effective when aged over a 4-d period. Traps baited with brown sugar captured the highest number of adults, and both baits were more attractive to females than males. Potential use of these baits for pest management and research is discussed, considering that this is the first report of pineapple juice being attractive to the papaya fruit fly.     

Biotransformation of pineapple juice sugars into dietetic derivatives by using a cell free oxidoreductase from Zymomonas mobilis together with commercial invertase

An easy procedure for cell free biotransformation of pineapple juice sugars into dietetic derivatives was accomplished using a commercial invertase and an oxidoreductase from Zymomonas mobilis. First, pineapple juice sucrose was quantitatively converted into glucose and fructose by invertase, thus increasing the concentration of each monosaccharide in the original juice to almost twice. In a second step, glucose-fructose oxidoreductase (GFOR) transformed glucose into gluconolactone, and fructose into the low calorie sweetener sorbitol. The advantage of using GFOR is simultaneous reduction of fructose and oxidation of glucose, allowing the continuous regeneration of the essential coenzyme NADP(H), that is tightly bound to the enzyme. The yield of GFOR catalyzed sugar conversion depends on initial pH and control of pH during the reaction. At optimal conditions (pH control at 6.2) a maximum of 80% (w/v) sugar conversion was obtained. Without pH control, GFOR is inactivated rapidly due to gluconic acid formation. Therefore, conversion yields are relatively low at the natural pH of pineapple juice. The application of this process might be more advantageous on juices of other tropical fruits (papaya, jackfruit, mango) due to their naturally given higher pH.     

Submerged acetification of a vinegar base produced from waste pineapple juice

Submerged acetification experiments were performed to determine conditions necessary for the production of a satisfactory vinegar from waste pineapple juice using a pure culture inoculum. Vinegars containing up to 7%, by weight of acetic acid could be produced in less than 24 hr. with a conversion efficiency greater than 90% in both laboratory and pilot plant equipment. None of the bacterial nutrients added to the juice improved either the rate of production or the yield of acetic acid. Oxygen transfer during the process is discussed.     

Lowering of oxidative stress improves endothelial function in healthy subjects with habitually low intake of fruit and vegetables: A randomized controlled trial of antioxidant- and polyphenol-rich blackcurrant juice

Inadequate intake of the recommended five-a-day fruit and vegetable portions might contribute to increased cardiovascular disease risk. We assessed the effects of dietary intake of a blackcurrant juice drink, rich in vitamin C and polyphenols, on oxidative stress and vascular function. This was a double-blind, placebo-controlled, parallel group study of 66 healthy adults who habitually consume <2 portions of fruit and vegetables per day. Participants were randomly allocated to consume 250 ml of placebo (flavored water) or low or high blackcurrant juice drink four times a day for 6 weeks. Flow-mediated dilation (FMD) and plasma concentrations of F₂-isoprostanes and vitamin C were measured. In the high blackcurrant juice drink group FMD increased significantly (5.8±3.1 to 6.9±3.1%, P=0.022) compared with the placebo group (6.0±2.2 to 5.1±2.4%). Plasma vitamin C concentration increased significantly in the low (38.6±17.6 to 49.4±21.0 µmol/L, P<0.001) and high (34.6±20.4 to 73.8±23.3 µmol/L, P<0.001) blackcurrant juice drink groups compared with the placebo group (38.1±21.0 to 29.0±17.6 µmol/L). F₂-isoprostane concentrations were significantly lower in the high blackcurrant juice drink group (225±64 pg/ml) compared with the low blackcurrant juice drink (257±69 pg/ml, P=0.002) and placebo group (254±59 pg/ml, P=0.003). At follow-up, changes in plasma vitamin C correlated significantly with changes in FMD (r=0.308, P=0.044). Consumption of blackcurrant juice drink high in vitamin C and polyphenols can decrease oxidative stress and improve vascular health in individuals with habitually low dietary fruit and vegetable intake.     

Tatumella ptyseos,an Unrevealed Causative Agent of Pink Disease in Pineapple

Pink disease is a major problem in the pineapple canning industry. Affected fruit acquire a brownish pigment after pasteurization and can contaminate non‐affected fruit before they are released to the consumer. In the last few years, Pantoea citrea has been described as the causative agent of pink disease. In this study, over 300 bacterial isolates from pineapple plants, growing in Mexican commercial fields, and from soil close to plant roots were recovered. Over 250 isolates showed a very high similarity in their phenotypic and genotypic traits with Tatumella ptyseos, a close relative of Pantoea. These isolates exhibited typical pathogenicity reactions in pineapple juice tests, pineapple slices and fruit. On this basis, molecular identification procedures for the Tatumella isolates associated with pink disease were implemented. In affected fruit populations around 10⁶ CFU/g of fresh tissue were recovered. This is first time that T. ptyseos is demonstrated as a causal agent of pink disease.     

Odor-active constituents in fresh pineapple (Ananas comosus [L.] Merr.) by quantitative and sensory evaluation

By application of aroma extract dilution analysis (AEDA) to an aroma distillate prepared from fresh pineapple using solvent-assisted flavor evaporation (SAFE), 29 odor-active compounds were detected in the flavor dilution (FD) factor range of 2 to 4,096. Quantitative measurements performed by stable isotope dilution assays (SIDA) and a calculation of odor activity values (OAVs) of 12 selected odorants revealed the following compounds as key odorants in fresh pineapple flavor: 4-hydroxy-2,5-dimethyl-3(2H)-furanone (HDF; sweet, pineapple-like, caramel-like), ethyl 2-methylpropanoate (fruity), ethyl 2-methylbutanoate (fruity) followed by methyl 2-methylbutanoate (fruity, apple-like) and 1-(E,Z)-3,5-undecatriene (fresh, pineapple-like). A mixture of these 12 odorants in concentrations equal to those in the fresh pineapple resulted in an odor profile similar to that of the fresh juice. Furthermore, the results of omission tests using the model mixture showed that HDF and ethyl 2-methylbutanoate are character impact odorants in fresh pineapple.     

Oxidative DNA damage in circulating mononuclear blood cells after ingestion of blackcurrant juice or anthocyanin-rich drink

Berry extracts possess antioxidant activity in cell free systems, whereas cell culture and animal experimental systems have produced mixed outcomes. Our aim was to investigate the effects of blackcurrant juice and specifically blackcurrant anthocyanins on the steady state level of oxidative DNA damage in mononuclear blood cells (MNBC) of humans, determined as strand breaks (SB) as well as endonuclease III (Endo III) and formamidopyrimidine DNA glycosylase (Fpg) sensitive sites by the comet assay. Fifty-seven healthy humans completed a 3-week controlled parallel intervention study with three groups randomized to supplementation with blackcurrant juice, anthocyanin drink, or a control drink. The daily doses ranged from 475 to 1000ml/d according to body weight (mean anthocyanin intakes in blackcurrant juice and anthocyanin drink groups were 397 and 365g/d, respectively) and they were ingested during three daily meals while all volunteers were on the same strictly controlled low-flavonoid diet. Fasting venous blood samples were obtained at baseline and after 3-week of supplementation. The baseline level of oxidative DNA damage was low (e.g. less than 200 Fpg lesions per diploid cell). Fpg sensitive sites increased during the intervention within the blackcurrant juice group, whereas there were no differences between treatments in any of the DNA damage markers. In conclusion, this study shows that even large amounts of dietary antioxidants did not decrease the already low steady state levels of oxidative DNA damage in healthy adequately nourished humans.