莴笋渗透脱水的试验研究

以莴笋为试验对象,在不同的渗透脱水条件下,对物料失水率和固形物增加率进行考察,探索莴笋的渗透脱水规律。通过试验研究发现,在蔗糖和食盐的组合渗透液中,高浓度的蔗糖能有效提高物料的失水率,并阻碍溶质的渗入;而提高温度可以加快传质速度,却不一定能提高物料的失水率;正交试验得到莴笋渗透脱水的较佳工艺条件为:温度30℃,固液比1∶10,渗透液为60%蔗糖+10%食盐浓度的组合渗透液。     

苹果渗透脱水的响应面优化分析

以渗透时间、渗透温度、渗透液浓度和反应的固液比为自变量,以失水率、固形物增加率,以及干燥后产品的复水率为应变量,对苹果进行渗透脱水响应面试验研究。应用响应面分析的方法对试验结果进行优化分析,得出最佳工艺为:渗透时间为110min,渗透温度为35℃,渗透液的浓度为40°Brix+质量分数为4.5%的NaCl,反应的固液比为1∶10。     

果蔬-开菲尔藜麦发酵混合冻干食品的研制及抗氧化特性分析

为研究以开菲尔藜麦发酵乳、沙棘原浆、黄桃浓浆和胡萝卜浓浆为原料的混合冻干食品工艺配方及抗氧化特性,以感官评分和可溶性固形物含量作为评价指标,通过单因素试验和正交试验确定最佳工艺配方,冻干、体外胃肠消化模拟后研究其黄酮和多酚含量、DPPH、羟基和超氧阴离子自由基清除率及铁还原力的动态变化.结果表明:开菲尔藜麦发酵乳、沙棘原浆、黄桃浓浆和胡萝卜浓浆的最佳质量比为50:13:30:10,在此条件下,可溶性固形物含量为19.9％,感官评分为81.4分,综合得分为63.0分,经过消化后,其黄酮和多酚含量均有所增加,DPPH自由基、羟基自由基和超氧阴离子自由基清除率及铁还原力均有显著增加(P<0.05).     

渗透脱水预处理对蓝莓冷冻融化后品质的影响

以蓝莓为试材,研究渗透脱水预处理对物料冷冻融化后品质的影响,设置-18℃普通缓冻和-80℃超低温速冻方式为对照组,静置渗透脱水冷冻和超声波辅助渗透脱水冷冻为试验组,测定蓝莓的冻结曲线、汁液流失率、硬度、色泽、可溶性固形物含量、花青素含量、过氧化物酶活性和多酚氧化酶活性。结果表明：静置渗透脱水预处理使蓝莓的冻结时间相对于普通缓冻缩短了9.41%,在可溶性固形物含量和硬度方面显著高于其他处理组（P<0.05）,保持了良好的色泽和外观品质,同时可以有效抑制酶活性;超声波辅助渗透脱水预处理虽然比静置渗透脱水预处理提高了蓝莓冻结速率,并对蓝莓花青素的保留具有和超低温速冻相近的效果,但在其他指标上显著低于普通渗透脱水预处理组（P<0.05）。研究认为：两种渗透脱水预处理均比-18℃冻藏效果更好,且静置渗透脱水冷冻蓝莓更适合保留物料的加工食用品质,超声波辅助渗透脱水预处理可以有效保留冻融蓝莓的花青素。     

胡萝卜 猕猴桃复合低糖果酱的研制

介绍了以选择胡萝卜、猕猴桃为原料生产的果酱。生产中采用低甲氧基果胶为凝固剂，可防止低糖果酱的脱水。通过正交试验，筛选出胡萝卜、猕猴桃复合低糖果酱的最佳配方和工艺，产品色泽自然，风味清香爽口。     

真空冷冻脱水胡萝卜预处理工艺及干燥特性的研究

胡萝卜是一种营养物质含量丰富,人们喜食的蔬菜产品。为解决常压热风干燥技术生产的出口脱水胡萝卜营养物质损失严重和色泽差等产品质量问题,系统研究了胡萝卜在真空冷冻干燥条件下的预处理工艺及干燥特性。研究结果表明,胡萝卜真空冷冻干燥最佳工艺参数为:85℃下漂烫75s,体积分数为0.15%的VC+体积分数为0.09%的柠檬酸中护色10min,装载总量100g,装载厚度为6mm下真空冷冻干燥10.4h。在最佳操作条件下获得的胡萝卜产品颜色损失小,质量较佳。     

组合式干燥机组在脱水蔬菜中的应用

脱水蔬菜是利用自然或人工方法使新鲜蔬菜脱去部分水分而制得的干菜。脱水蔬菜基本保持了蔬菜原有的色泽、味道和营养成分,食用方便,同时由于含水量少、容易运输、贮藏时间长,能有效地调节蔬菜生产的淡旺季。脱水蔬菜的主要品种有胡萝卜、食用菌类、白菜、甘蓝和生姜等,脱水干制方法有自然晒干及人工脱水两类。     

超声波辅助碱法提取蕨菜中水溶性膳食纤维

采用超声波辅助碱法提取蕨菜中的水溶性膳食纤维(SDF),通过单因素试验探讨料液比、超声功率、碱液质量浓度、提取温度4个因素对SDF得率的影响,再通过正交试验对提取工艺条件进行优化。结果表明,超声波辅助碱法提取蕨菜中的SDF最佳工艺条件为氢氧化钠质量浓度0.06 g/mL,超声功率120 W,料液比1∶30(g∶mL),提取温度65℃,实际测得SDF得率为36.01%。     

果胶酶对樱桃提汁效果的研究

采用酶解法提取樱桃汁,研究果胶酶不同浓度对樱桃出汁率的影响,并通过对汁液的澄清度、可溶性固形物含量和透光率的测定分析,确定提汁的最佳果胶酶浓度。实验结果表明,果胶酶对樱桃出汁率的影响较显著。在室温下,添加不同的果胶酶量0,0.02%,0.04%,0.06%,0.08%,0.10%,0.12%,酶解8 h后,测得酶质量分数为0.10%时的出汁率最高,达到59.7%,比对照组提高了14%,并且极大地降低了果汁的黏度,使果汁澄清度加大,可溶性固形物含量明显提高。实验结果还表明,澄清樱桃汁的最大透光率波长为620 nm,当果胶酶质量分数达到0.10%时,汁液的透光率达到92%,可溶性固形物含量为13.8%,樱桃汁的品质比对照组都有较大的提高。     

白枇杷保鲜技术的研究

以宁海白枇杷为试验材料,对其在不同温度和湿度条件下的保鲜贮藏效果进行试验研究,通过测定白枇杷不同处理在贮藏过程中的腐烂率、硬度、可溶性固形物及酸含量的变化,探讨白枇杷的最佳贮藏条件。     

不同频率下超声波水处理对苹果内传热传质影响规律的试验研究

为探究超声波处理对果蔬加工过程中热质传递的影响规律,以苹果为研究对象,结合不同频率（40、68、80 kHz）超声波处理技术,分别进行超声波辅助低温水浴试验和超声波水预冷处理辅助苹果片真空冷冻干燥试验。结果表明：超声波辅助低温水浴可有效强化苹果与冷水间的热量交换,频率为80 kHz时,苹果果肉中部和近果核处的冷却系数与对照组相比分别增加了35.3%和28.6%;超声波水预冷处理后,真空冷冻干燥过程有效水分扩散系数比对照组分别增加了51.6%（超声波频率40 kHz）、55.9%（超声波频率68 kHz）、58.7%（超声波频率80 kHz）。     

微波干燥过程中的土豆组织温度变化及水分迁移特性

为探索淀粉类果蔬多孔介质在微波干燥过程中的热质传递特性,以土豆为研究对象,测量其不同功率下微波干燥过程中土豆组织的温度和质量以及水分状态变化。结果表明,微波干燥过程中土豆组织的温度可以分为快速升温、恒温及降温段3个阶段,土豆质量减少主要发生在恒温段,且该阶段物料的失重率占总失重率的90%以上。微波干燥过程中自由水短暂升高至93.21%后逐渐降低至15.61%,而不易流动水和结合水均先降低后升高。淀粉对于微波干燥中的水分迁移有重要影响,淀粉失去薄膜水后固化,使得土豆片的骨架硬度增加,从而增大水分迁移阻力。     

水分胁迫期间及解除胁迫后对胡萝卜生长及叶细胞结构的影响

以盆栽胡萝卜品种向阳二号为材料,研究不同程度水分胁迫及胁迫解除后对胡萝卜生长的影响,旨在为胡萝卜耐旱栽培提供理论依据。结果表明,水分胁迫对胡萝卜的生长影响很大,当缺水严重时,叶片及根的生长均受到明显抑制,使苗的生长量、干物质积累及含水量显著下降。而且即使解除胁迫后其生长及各项指标也难以恢复。水分胁迫对叶细胞结构也有很大影响,随着水分胁迫程度的增强,细胞核数量减少,核缩小、变形或降解,解除胁迫以后也很难恢复。     

脉冲超声嫩化香菇柄的研究

以新鲜香菇柄为原料,通过单因素试验和正交试验,研究脉冲超声处理对香菇柄的嫩化效果。结果表明,单因素各试验组的咀嚼性均低于未嫩化处理的对照组,各单因素最佳水平的嫩化率均大于40%,嫩化效果明显。正交试验优化的超声波嫩化香菇柄最优工艺为:超声功率650 W、脉冲超声时间5 min、超声/间隙时间4 s/2 s,此条件下处理的香菇柄咀嚼性为18.98 m J。验证试验结果表明,脉冲超声处理香菇柄的嫩化率比普通连续超声高51.28%,说明脉超声非常适用于香菇柄的嫩化处理。     

The relationship between water status and chlorophyll a fluorescence in grapes (Vitis spp.)

The purpose of this study was to explore the utility of chlorophyll fluorescence to non-destructively monitor water status in plant tissue, specifically water loss in grapes (Vitis spp.) destined for wine production. An automated remote-sensing (ARS), pulse amplitude modulation (PAM) fluorometer prototype, capable of scanning a large surface area, was used to monitor chlorophyll fluorescence from ‘L’Acadie’ (LAc) and ‘Thompson Seedless’-type (TS) grape clusters during postharvest dehydration. Increasing mass loss (%) in grapes correlated with increasing soluble solids (SS) content and decreasing osmotic potential (Ψ_s) (p < 0.001). All of the primary fluorescence parameters monitored (F₀, F_m, F_v and F_v/F_m) had a strong curvilinear relationship (p < 0.001) with grape mass loss. In both cultivars, F₀ increased during the later stages of dehydration, likely as a result of increased disorder within the thylakoid membranes and/or a reduction in energy transfer between LHCII and PSII. F_m, F_v and F_v/F_m declined, likely due to several factors that are known to inhibit photosynthesis and the primary charge recombination during osmotic stress. Chlorophyll degradation during dehydration was a major factor influencing cultivar differences in the fluorescence relationships. An inflection point in the F₀ value at ≈20–25% mass loss appeared to correspond with an inflection point in the decreasing glucose:fructose ratio. The relationship between chlorophyll fluorescence and water loss, SS, Ψ_s and potentially other indicators of metabolic change, could lead to practical applications of this technology in the slow dehydration of grapes and other fruits used to make high value wines.     

Effect of chitosan-based edible coatings applied by vacuum impregnation on quality preservation of fresh-cut carrot

Edible coatings based on high molecular weight chitosan, pure or combined with methylcellulose or oleic acid, were applied to fresh-cut carrots cv. Nantesa by simple immersion and by applying a vacuum pulse (5 kPa for 4 min). Water vapour resistance, colour, mechanical properties and respiration rates of non-coated and coated samples were determined. Coatings improved sample appearance, since they diminished the occurrence of the white blush during storage. When applied by simple immersion, they neither conferred significant barrier properties nor the preservation of the mechanical properties of fresh-cut carrot samples. In contrast, coating application with a vacuum pulse enhanced all the positive effects, since the resistance of water vapour transmission of the samples was significantly improved, and better preservation of the sample colour and mechanical response during cold storage was obtained. Differences in film composition did not significantly affect the coating behaviour, probably due to the variability induced by different factors when coatings were applied to the carrot surface.     

Application of Low Intensity Ultrasound to Biotechnology

Application of low intensity ultrasonic waves to the biotechnology is one of new and hot research fields. The physical mechanisms of ultrasound mainly include the effects of mass transfer ,heating and cavitation. Many researchers found that low intensity ultrasonic waves could accelerate the interacton of substrate and help reactant to enter the active center of enzyme and production to leave center; it could also alter the permeability of membrane and enhance the transfer of mass, and so promote the production of beneficial matter and the absorption of drug to cells; in addition ,it could raise the efficiency of cell metabolism and the growth of cells; so low intensity ultrasonic waves can be used in enzyme engineering, fermentation engineering, cell engineering and biological therapeutics of Neoplasm. In this paper, we reviewed the application of low intensity ultrasound to biotechnology at home and abroad.     

Intact Plant, Callus and Field Grain Yield Responses of Tepary Bean to Drought

In a field trial involving four tepary lines (Phaseolus acutifolius A. Gray), NE#8A and NE#19 produced higher grain yield than NE#5 and NE#7 under both well watered and drought conditions. However, NE#8A is considered more resistant than NE#19 in terms of drought sensitivity index. Greenhouse investigations on intact plants indicated no differences among the four lines in leaf and stem dry mass, and leaf area. Root depth did not strictly differentiate lower‐yielding from higher‐yielding lines. In contrast to lower‐yielding lines, however, plants of higher‐yielding ones allocated greater dry matter (DM) in roots in response to imposed water stress. Distinctly, NE#19 had the greatest root : shoot (R : S) while NE#8A characterized by high net photosynthesis. Both NE#8A and NE#19 showed reduced leaf area : root dry mass ratio, stomata conductance and transpiration rate. Consequently, these two lines showed no significant changes in leaf relative water content while photosynthetic water‐use‐efficiency increased in response to water stress. Calli derived from leaf and root tissues of higher‐yielding lines exhibited low initial osmotic potential (ψ_s). These calli did not show alterations in ψ_s, DM% and relative growth rate (RGR) when subjected to water stress. Although leaf‐ and root‐derived calli of lower‐yielding lines exhibited osmotic adjustment, they suffered water stress in terms of elevated DM and reduced RGR. Overall, results suggest that dehydration‐avoidance mechanisms conditioned by increased root mass and stomata resistance accompanied with low initial cellular ψ_s sustained high grain yield of tepary under limited water supply.