冻结方式和冻藏条件对水蜜桃果浆冻藏期间抗氧化特征的影响

目的：研究液浸速冻和低压静电场对冻藏水蜜桃果浆氧化特征的影响。方法：以气流速冻处理组为对照，分析了冻藏期间果浆在抗氧化能力、氧化底物、相关酶活力等方面的变化。结果：液浸速冻处理果浆的抗氧化能力损失较气流速冻更大，冻藏期间使用低压静电场可以抑制抗氧化能力的损失。氧化底物的保留率依次为低压静电场+液浸速冻>液浸速冻>气流速冻。冻藏期间的酶活力依次为气流速冻>液浸速冻≥低压静电场+液浸速冻。结论：液浸速冻加工并用低压静电场辅助冻藏的水蜜桃果浆具有更好的抗氧化特征。     

核桃/刺梨复合种植对刺梨生长、果实产量、品质和土壤性质的影响

核桃和刺梨是西南山区栽培的2种重要乔灌果树,二者在该区域存在复合种植。本研究以贵州地区具有代表性的核桃(‘黔核7号’)/刺梨(‘贵农5号’)复合种植模式为对象,研究了复合种植7年时刺梨的生长、产量、果实品质、光合作用及土壤肥力等情况。结果表明：与单一种植模式相比,复合种植中刺梨叶片光合色素含量和光合速率显著降低;刺梨长势和产量显著下降,其中产量下降高达77.7%;刺梨的果实品质有所提升,果实中抗坏血酸(Vc)、总酚、糖类物质以及钾、钙、镁、铁、锰、锌等含量显著提高,其中果实Vc和锰含量分别提高34.1%和64.1%。复合种植刺梨土壤中全氮、有效态氮和有效态钾含量分别提高45.8%、34.8%和67.8%;土壤微生物数量和功能菌数量也明显增多,其中细菌和真菌的增幅均达36.0%以上,钾细菌和固氮菌分别提高71.3%和124.8%;土壤有机质、碳氮比、全磷、全钾及有效态矿质养分(磷、钙、镁、铁、锰、铜、锌)含量下降;除土壤脲酶和过氧化氢酶活性提高外,其余土壤酶(蔗糖酶、纤维素酶、蛋白酶、磷酸酶)活性都显著降低。综上,在核桃/刺梨复合种植林中,随着核桃植株的不断生长,其对刺梨存在明显的遮阴和...     

刺梨果实膳食纤维积累动态及其对遮光的反应

刺梨果实是优质膳食纤维的良好来源。该研究以‘贵农5号’刺梨果实为材料,测定了果实发育过程中膳食纤维的含量、组分变化及其对光照的响应特征。结果表明:(1)在刺梨果实的整个发育过程中,总膳食纤维和不溶性膳食纤维含量在花后40 d之前的幼果期更高,并随着果实的快速发育持续下降,至成熟时分别约占果实干重的24%和16%,而可溶性膳食纤维含量在果实发育过程中变化平稳,一直维持在干重的8%左右。(2)果胶在花后20 d之前有一快速积累过程,至果实成熟时纤维素和半纤维素为膳食纤维主要组分,约占总膳食纤维的60%;花后60 d之前是刺梨果实膳食纤维积累的主要时期。(3)刺梨果实总膳食纤维、不溶性膳食纤维中单糖组分主要以半乳糖、葡萄糖为主,而可溶性膳食纤维中单糖组分主要为甘露糖,两类膳食纤维间表现出较大差异。(4)果实套袋遮光不同程度促进了刺梨果实总膳食纤维、可溶性膳食纤维、总果胶、原果胶的积累,尤其是100%遮光的效应更明显,但对果实中不溶性膳食纤维、纤维素、木质素、可溶性果胶的积累影响并不显著。     

冷藏方式对桃采后果胶含量和β-半乳糖苷酶活性的影响

以采后包装和不包装的'大久保'桃果实为材料,分别测定了其在8℃冷藏(A)、8℃冷藏10 d后转入0℃贮藏(B)和0℃冷藏(C)方式下的硬度、出汁率、果胶含量和β-半乳糖苷酶活性的变化.结果表明:在A、B冷藏方式下,包装较不包装处理显著抑制了果实的硬度下降、原果胶含量减少和可溶性果胶含量增加,降低了果实出汁率和β-gal活性;与冷藏期比较,货架期后冷藏方式A和B果实表现为硬度下降、原果胶含量减少、可溶性果胶含量增加,以及出汁率和β-gal活性升高.与冷藏方式A和B比较,冷藏方式C果实的硬度和原果胶含量较高,出汁率和可溶性果胶含量较低;货架期后,不包装的果实硬度和原果胶含量增加,可溶性果胶含量和β-gal活性降低,但包装处理却能减缓上述现象的发生.研究表明,桃采后用30 μm聚乙烯袋包装、于8℃冷藏10 d后转入0℃贮藏处理,能使桃果实在贮藏期保持较低的可溶性果胶含量和较高的原果胶含量和出汁率,并能使桃在货架期正常后熟软化,是贮藏桃的一种较好方式.     

刺梨自然发酵过程中非酿酒酵母多样性分析

【目的】分析刺梨果实自然发酵过程中非酿酒酵母菌群特征,为筛选优质刺梨非酿酒酵母提供参考。【方法】基于Illumina MiSeq高通量测序技术和WL营养琼脂鉴定培养基纯种分离技术,分析刺梨果实自然发酵1 d (F1)、3 d (F3)、5 d (F5)和15 d (F15) 4个阶段及YPD培养基富集培养样本中非酿酒酵母种群组成和多样性。【结果】高通量测序分析结果共获得182个OTUs (operational taxonomic units,OTUs),归属于81个属107个种;物种多样性分析结果表明,刺梨果实自然发酵前期,优势非酿酒酵母为汉逊酵母(Hanseniasporasp.)和伯顿丝孢毕赤酵母(Hyphopichiaburtonii),二者在样本F1中分别占42.59%和26.85%;随着自然发酵的不断进行,二者的比例逐渐降低,在第15天(F15),Hanseniaspora sp.和H. burtonii比例降低至7.73%和0.52%。相反,Pichia sporocuriosa和未培养的酵母,随着自然发酵不断进行所占比例逐渐增大,分别由F1中的0.23%和0.33%增至F15中的37.26%和32.62%。此外,采用WL营养琼脂鉴定培养基纯种分离和鉴定技术,从刺梨上分离到Hanseniasporasp.、H.burtonii、克鲁维毕赤酵母(Pichia kluyveri)、P. sporocuriosa和异常威克汉姆酵母(Wickerhamomyces anomalus) 5种类型的可培养非酿酒酵母。【结论】刺梨果实上存在着丰富的非酿酒酵母菌资源,研究刺梨自然发酵过程中非酿酒酵母多样性,为酵母资源开发和利用奠定基础。     

蓝靛果忍冬的药理功能及作用机理的研究

蓝靛果忍冬又名蓝靛果、黑瞎子果、山茄子等,果实出汁率高,是制作饮料的极好原料,被誉为"饮料之王"。经深入研究发现蓝靛果中含有丰富的Vp活性物质,如花青甙、芸香甙,儿茶酸等,具有很高的药用价值。蓝靛果不但有较高的抗氧化性、抗肿瘤作用,还可以治疗胃溃疡、预防心脑血管疾病等。     

遮光对刺梨果实和叶片中维生素C与糖含量以及相关酶活性的影响

为探究光照强度减弱对不同发育期的刺梨(Rosa roxburghii Tratt.)果实和叶片中维生素C与糖含量及相关酶活性的影响,以‘贵农5号’刺梨扦插苗为材料,采用遮阳网设置光强减弱20%、40%、60%的3个遮光处理,以自然光照强度为对照(CK),分析不同光照强度条件下刺梨果实和叶片中维生素C含量及相关酶活性以及糖含量的变化。结果表明：(1)光照强度减弱后,不同发育期的刺梨果实和叶片中维生素C含量均显著降低,对照及3个处理间的果实维生素C含量的差异在快速膨大期均达到显著水平。(2)随着光照强度的减弱,刺梨果实和叶片中L 半乳糖 1,4 内酯脱氢酶(GalLDH)、单脱氢抗坏血酸还原酶(MDHAR)和脱氢抗坏血酸还原酶(DHAR)活性均降低,而抗坏血酸氧化酶(AAO)和抗坏血酸过氧化物酶(APX)活性均增强,尤其是果实中MDHAR活性在快速膨大期迅速大幅增强。(3)刺梨果实和叶片中可溶性糖、蔗糖、葡萄糖、果糖含量随光照强度减弱而降低,但果实中葡萄糖含量在快速膨大期增加尤为迅速。(4)果实中维生素C含量与叶片中蔗糖、葡萄糖含量在不同发育期均呈极显著正相关关系,快速膨大期果实中GalLDH、MDHAR活性与维生素C含量呈极显著正相关关系且相关系数均达到最大值,而其APX活性与维生素C含量呈极显著负相关关系且相关系数达到最大值。研究认为,光照强度通过调控刺梨果实中维生素C合成及相关代谢关键酶的活性与叶片中光合产物的含量最终影响果实中维生素C的积累量;弱光环境不利于刺梨果实和叶片中维生素C及糖的积累,其影响在果实快速膨大期尤为明显;良好的光照是保证刺梨果实优良品质的基本条件。     

温室滴灌条件下土壤水分亏缺对番茄产量及其形成过程的影响

采用小区试验,在温室滴灌条件下研究了不同生育阶段土壤水分状况对番茄果实大小、坐果数、畸形果及产量形成过程的影响,分析了温室滴灌条件下番茄总产量与灌水量的关系.结果表明：番茄苗期适度水分亏缺（田间持水量的50%～55%）可提高坐果率,畸形果形成减少,但果实总体偏小,果实成熟主要集中在采摘后期;开花坐果期过度水分亏缺（田间持水量的65%以下）虽可促进果实成熟,但降低了坐果数,易形成小果和畸形果;采摘期水分过高（田间持水量的80%以上）或过低（田间持水量的65%以下）均可降低番茄产量,水分亏缺（田间持水量的65%以下）则使坐果数降低、畸形果增加.各水分处理对果实成熟时间无明显影响;温室番茄总产量、灌溉水利用效率与全生育期灌水总量之间均呈二次抛物线关系;当番茄土壤水分（占田间持水量的百分比）下限控制在苗期60%～65%、开花坐果期70%～75%、成熟采摘期70%～75%时,番茄畸形果形成量减少,产量及坐果率较高,可作为滴灌条件下温室番茄适宜的土壤水分控制指标.     

水分和盐分胁迫对番茄植株生长和木质部水力特性的影响

木质部是植株体内水分传输的主要通路,其水力特性的变化会影响植株的水分关系和果实的水分积累。目前关于番茄植株木质部解剖结构和水力特性对水分和盐分胁迫的响应及其与植株生长和果实含水量之间的关系尚不明确。本研究通过日光温室番茄盆栽试验,设置3个处理:对照,土壤含水量(θ)为75%～95%田间持水量(FC),初始电导率(EC)为0.398 dS·m^-1;水分胁迫,开花前θ为75%～95% FC,开花后至成熟期θ为45%～65% FC,EC为0.398 dS·m^-1;盐分胁迫,θ为75%～95% FC,EC为1.680 dS·m^-1,研究了樱桃型番茄(红宝石)和中果型番茄(北番501)植株在水分和盐分胁迫下的植株生长、果实含水量以及木质部水力特性的变化。结果表明: 与对照相比,水分和盐分胁迫下茎秆横截面积和木质部导管直径分别减小了22.0%～40.7%和10.0%～18.3%,茎秆比导水率和桁架柄比导水率分别降低了8.8%～41.1%和12.9%～28.4%,抑制了植株生长,减少了地上部鲜重、果实大小、果实鲜重和含水量,且与樱桃型番茄相比,中果型番茄的降幅更大。此外,果实含水量分别与茎秆和桁架柄比导水率呈显著正相关。综上,番茄植株在水分和盐分胁迫下木质部水力特性指标减小,生长被抑制,果实鲜重显著降低,最终导致产量降低。其中,中果型番茄相较于樱桃型番茄对水分和盐分胁迫更敏感。     

星油藤蒴果及种子的性状变异研究

为进行星油藤(Plukenetia volubilis L.)良种选育,对其蒴果和种子的性状变异进行了研究。结果表明,星油藤蒴果中4、5、6裂片果分别为49.71%、37.69%和12.60%,以4和5裂片为主;种子性状变异系数比果实的小,种子性状比果实更稳定。按果裂片类型统计,以4裂片的性状变异系数最小,性状也较为稳定,性状分化变异率有54.19%~95.63%来自蒴果间,而果实和种子性状分化变异率分别有79.81%~95.76%和67.66%~93.0%来源于裂片类型,性状分化变异受裂片数影响大,而相同裂片数不同蒴果间的变异程度低。不同裂片类型的果实与种子大多数性状间均存在显著或极显著差异,果裂数是造成性状差异的主要原因。种子萌发率以6裂片果5裂片果4裂片果,平均萌发率超过91%;种子萌发率与单果重、单果重与果形态指标、种子重与种子形态性状间均存在极显著正相关关系,其中单果重对果厚、种子重对种子宽的影响大于其它性状。综合分析星油藤以4裂片果的生物产量最高,平均果重和种子重均好于其他类型。     

羊奶果果实加工技术

羊奶果果实鲜食涩味大,从去除果实的涩味入手,研究加工技术,研制出色泽乳白、风味独特的羊奶果天然果汁饮料和酸甜可口的羊奶果蜜饯,提高了其经济价值。     

Effects of early plant growth regulator treatments on flavonoid levels in grapefruit

Early foliar spray treatments containing gibberellic acid(GA₃) significantly lower the concentration ofthe bitter flavonoid naringin in fruit tissues. Sprayscontaining a surfactant and different levels ofGA₃ (5, 50, 100, and 500 ppm) or abscisic acid(ABA) (5, 25, and 50 ppm) were applied to young,developing fruit on mature grapefruit (Citrusparadisi) trees during the period from April to June,beginning just after fruit set. The fruit were allowedto mature and were harvested early the following year.Harvested fruit were evaluated for weight, juicecharacteristics, and flavonoid concentrations.GA₃ application resulted in larger mature fruit,which yielded juice with the same soluble solids valueas juice from control fruit, but with slightly loweracid percentages and lower concentrations of naringin.ABA treatment had little effect on juice solublesolids, acid content and naringin content except atthe highest concentration of 50 ppm, which lowerednaringin levels slightly in juice.     

Effect of continuous ohmic heating to inactivate Escherichia coli O157:H7, Salmonella Typhimurium and Listeria monocytogenes in orange juice and tomato juice

Aims: The purpose of this study was to investigate the efficacy of continuous ohmic heating for reducing Escherichia coli O157:H7, Salmonella Typhimurium and Listeria monocytogenes in orange juice and tomato juice. Methods and Results: Orange juice and tomato juice were treated with electric field strengths in the range of 25–40 V cm^?1 for different treatment times. The temperature of the samples increased with increasing treatment time and electric field strength. The rate of temperature change for tomato juice was higher than for orange juice at all voltage gradients applied. Higher electric field strength or longer treatment time resulted in a greater reduction of pathogens. Escherichia coli O157:H7 was reduced by more than 5 log after 60‐, 90‐ and 180‐s treatments in orange juice with 40, 35 and 30 V cm^?1 electric field strength, respectively. In tomato juice, treatment with 25 V cm^?1 for 30 s was sufficient to achieve a 5‐log reduction in E. coli O157:H7. Similar results were observed in Salm. Typhimurium and L. monocytogenes. The concentration of vitamin C in continuous ohmic heated juice was significantly higher than in conventionally heated juice (P < 0·05). Conclusions: Continuous ohmic heating can be effective in killing foodborne pathogens on orange juice and tomato juice with lower degradation of quality than conventional heating. Significance and Impact of the Study: These results suggest that continuous ohmic heating might be effectively used to pasteurize fruit and vegetable juices in a short operating time and that the effect of inactivation depends on applied electric field strengths, treatment time and electric conductivity.     

双歧杆菌发酵果蔬汁中低聚果糖的高效液相色谱法分析

目的采用高效液相色谱法（HPLC）对双歧杆菌发酵果蔬汁中的低聚果糖进行分析。方法 HPLC分析条件为：ZORBAX NH2 Analytical色谱柱,乙腈∶水（75∶25）为流动相,柱温35℃,流速为1.0ml/min,示差折光检测器（RID）。结果果蔬汁中的低聚果糖及几种主要糖类均得到有效分离。此分离方法的加标回收率和精密度（RSD）均较高。结论分析结果表明双歧杆菌发酵果蔬汁中含有较丰富的功能性低聚果糖,尤其是蔗果三糖含量很高。     

双歧杆菌发酵果蔬汁营养成分分析及保质期观察

目的分析双歧杆菌发酵果蔬汁的营养成分及保质期观察。方法采用各种营养分析方法对双歧杆菌发酵果蔬汁进行主要营养成分的分析测定。结果双歧杆菌发酵果蔬汁营养丰富,含有蛋白质、脂肪、糖、水溶性维生素和多种微量元素,含有18种氨基酸,8种人体营养必需氨基酸。结论双歧杆菌发酵果蔬汁营养成分丰富,保质期长,作为一种营养食品饮料值得推广应用。     

Glutathione and Cinnamic Acid: Natural Dietary Components Used in Preventing the Process of Browning by Inhibition of Polyphenol Oxidase in Apple Juice

Consumer demands for ‘freshness’ in processed foods has been given increasing attention by food processing industries by searching for minimally processed products. Polyphenol Oxidase (PPO) mediated browning is a major cause of undesirable flavors and nutritional losses in fruit juices. Here the anti-browning efficiency of glutathione (GSH, reduced form) and cinnamic acid (CA) in apple juice is evaluated. It was observed that the rate of the browning reaction could be efficiently delayed using GSH and CA, which act as inhibitors of PPO. Kinetic studies confirm that GSH and CA are non-competitive and competitive inhibitors of PPO respectively.     

THE YEAST FLORA OF APPLE JUICES AND CIDERS

SUMMARY: The yeast flora of a bulk of apples was followed through the different stages of cider making to the finished product. Yeasts on the fruit, and in the juice from an experimental plant, were mainly asporogenous. In a commercial sized plant, the juice was contaminated with yeasts present on the racks and cloths. Treating the juice with sulphur dioxide improved the yeast flora during fermentation; some controlling factors are considered. The efficiency of centrifugation depended on the pH of the juice, on sulphiting and on the loss of specific gravity that had previously taken place.     

柑橘皮中生理活性成分提取工艺研究进展

柑橘类水果是全世界最大宗产量的水果之一;皮渣作为其主要副产物占柑橘总量的20％～40％,具有较大的利用价值。本文综述了柑橘类主要副产品（香精油、果胶、天然色素、膳食纤维、黄酮类化合物和类柠檬苦素）的功能特性,以及国内外对这些物质的研究提取情况;并对我国柑橘加工产业提出了建议。     

Role of Alicyclobacillus acidoterrestris in the development of a disinfectant taint in shelf-stable fruit juice

AIMS: This study was undertaken to identify the bacterium and metabolic products contributing to a disinfectant taint in shelf-stable fruit juice and to determine some of the growth conditions for the organism. METHODS AND RESULTS: Microbiological examination of tainted and untainted fruit juice drinks detected low numbers of acid-dependent, thermotolerant, spore-forming bacteria in the tainted juices only. The presence of omega-cyclohexyl fatty acids was confirmed in two of the isolates by cell membrane fatty acid analysis. The isolates were subsequently identified as Alicyclobacillus acidoterrestris by partial 16S rDNA sequencing. Studies on the isolates showed growth at pH 2.5-6.0 and 19.5-58 degrees C. Gas chromatography/mass spectrometry (GC/MS) was used to identify and quantify 2,6-dibromophenol (2,6-DBP) and 2,6-dichlorophenol (2,6-DCP) in the tainted juice. Challenge studies in a mixed fruit drink inoculated with the two isolates and the type strain of A. acidoterrestris, incubated at 44-46 degrees C for 4 d, showed the production of both metabolites, which were confirmed and quantified by GC/MS. CONCLUSIONS: The results show that A. acidoterrestris can produce 2,6-DBP and 2,6-DCP in shelf-stable juices. SIGNIFICANCE AND IMPACT OF THE STUDY: This is the first report detailing experimental methodology showing that A. acidoterrestris can produce 2,6-DCP in foods. Control of storage temperatures (to < 20 degrees C) immediately after processing may provide an effective control measure for the fruit juice industry to prevent spoilage by A. acidoterrestris.     

荸荠汁对果蝇生长发育的影响

在正常果蝇培养基上每日添加荸荠汁,显著提高果蝇繁殖率,加速幼虫发育,增加成虫体重和身长。