真空浸渍法制备固定化乳酸菌苹果粒的研究

真空浸渍可将保加利亚乳杆菌和嗜热链球菌富集到苹果组织间隙,从而获得富集乳酸菌的苹果粒制品。本实验采用响应曲面法结合单因素实验对抽真空温度、抽真空时间和浸渍时间等因素进行了优化。结果表明,温度35℃,抽真空时间10min,浸渍时间80min时,苹果粒对乳酸菌吸附率最高,达到80%以上。同时实验表明冷冻干燥的效果明显优于热风干燥。冷冻干燥的苹果粒色泽鲜亮,外形饱满,口感松脆,具有苹果的芳香,乳酸菌活菌达≥109CFU/g。     

咸酥花生加工中的浸渍工艺研究

盐水浸渍是咸酥花生加工中的一个重要工序,本文比较研究了盐水常压浸渍和真空浸渍对花生品质的影响,并应用正交试验优化盐水真空浸渍花生的工艺参数。结果表明:盐水真空浸渍的花生品质优于常压浸渍,在常压、浸渍温度25℃下,浸渍18 h的花生盐水吸收率仅为45.26%、可溶性蛋白质含量降低0.81%;而在真空度0.085 MPa、浸渍温度25℃下,浸渍1 min的花生盐水吸收率可达100%,且可溶性蛋白质含量仅降低0.02%。盐水真空浸渍花生的最佳工艺参数为真空度0.085 MPa、浸渍温度55℃、盐水浓度10%(W/W)、浸渍时间3 min,在该工艺参数下的咸酥花生的感官品质最佳。     

真空冷冻干燥工艺参数对植物乳杆菌MA2活性的影响

试验主要研究了预冻温度、预冻时间、保护剂配方、保护剂与菌泥比例、物料厚度等真空冷冻干燥工艺参数对植物乳杆菌MA2活性的影响,并对真空冷冻干燥过程中菌粉的含水量进行了动态监测,绘制了物料升温曲线图,最终确定了合适的真空冷冻干燥工艺为预冻温度70℃;预冻时间2h;保护剂与菌泥的比例为1∶3;保护剂配方为脱脂奶粉10％,海藻糖1.5％,甘油0.5％,山梨醇2％,麦芽糊精1％;冻干厚度为1.5cm,该工艺条件下植物乳杆菌MA2真空冷冻干燥后的菌体存活率达61％,活菌数为1.50× 1012cfu/g.经复水试验证明,真空冷冻干燥后的菌体活性保持良好,证明该工艺具有良好的应用推广前景.     

高活性副干酪乳杆菌冻干菌粉的制备及工艺优化

目的:优化副干酪乳杆菌多种冻干保护剂的配比和真空冷冻干燥工艺参数,提高发酵剂的活菌含量,为冻干菌粉的制备提供指导。方法:以存活因子为指标,通过单因素实验筛选大分子保护剂、糖类、聚合物类、抗氧化剂类保护剂,应用正交试验优化保护剂配比,并通过单因素分析冷冻干燥的工艺参数,采用扫描电子显微镜观察冻干菌体形态。结果:副干酪乳杆菌冻干保护剂配方为:脱脂奶粉15%,蔗糖20%,聚乙烯吡咯烷酮(PVP K-30) 7%,谷胱甘肽(GSH)1.3%;真空冷冻干燥的工艺参数为在15℃下预处理2 h,保护剂pH为6.5,菌液和保护剂的比例为1∶1.5 (v/v),冻干厚度为0.5 cm,预冻方式为在液氮(-196℃)下处理15 min。在此条件下,副干酪乳杆菌经真空冷冻干燥后存活因子达(0.998±0.001),活菌数为(2.35±0.02)×1011CFU/g。经电镜观察发现菌体形态饱满,结构完整。结论:研究结果表明优化后的冻干保护剂及冻干工艺参数适用于副干酪乳杆菌菌体的保存,菌体活性保持良好,该工艺具有良好的应用推广前景。     

益生菌植物乳杆菌G1-28复合冻干发酵剂制备及保藏条件研究

为延长益生菌菌种的保藏时间,提高细胞存活率,以具有体外降胆固醇降甘油三酯功能的植物乳杆菌G1-28为菌种,对离心条件、冻干发酵保护剂配方及保藏条件进行了研究和优化。以活细胞收集率为指标,研究了菌悬液离心转速和时间对细胞收集率的影响;通过单因素实验及正交试验优化了植物乳杆菌的冻干保护剂并以存活率为指标,研究了真空条件和保藏温度对植物乳杆菌G1-28冻干发酵剂保藏效果的影响。结果表明,植物乳杆菌G1-28菌悬液的离心收集条件为5000 r/min,20 min,在此条件下活细胞收集率为96.26%;在脱脂乳7%,海藻糖2%,山梨醇3%,甘油4%条件下,细胞存活率最大为93.20%;最佳保藏条件为抽真空条件下?20 ℃保藏,保藏4个月后其存活率为97.1%,研究结果可为植物乳杆菌G1-28益生菌发酵剂的制备及降胆固醇降甘油三酯功能性食品的开发奠定基础。     

产肌醇的植物乳杆菌ZJ2868菌粉制备工艺

为研究产肌醇的植物乳杆菌ZJ2868的菌粉制备工艺,以菌体的存活率为指标,研究植物乳杆菌ZJ2868菌粉制备过程中的离心转速、保护剂配方、菌粉复溶条件和菌粉贮藏稳定性。结果:菌体收集的最佳离心条件:4 000 r/min、10 min。最佳冻干保护剂配方:谷氨酸钠11%、脱脂乳14%和海藻糖9.0%。最佳复溶条件:在原保护介质中复溶30 min。最佳贮藏温度:4℃。制得植物乳杆菌ZJ2868冻干菌粉的活菌数为2.90×109CFU/mL,存活率达85.4%,水分含量3.7%。本研究结果为植物乳杆菌菌粉的制备提供了试验依据。     

真空浸渍在果蔬加工中的应用

真空浸渍(VI)是将真空技术引入传统的浸渍过程的一种新技术,它能快速地将外部溶液渗入到动、植物组织的结构中,从而改变食品的组分.真空浸渍在果蔬加工中可以有广泛的应用,并有它特殊的优点.本文介绍了果蔬真空浸渍过程中的主要影响因素,总结了该技术近年来用于果蔬加工业的重要进展,最后对真空浸溃技术的应用前景进行了展望.     

豌豆蛋白酶解产物促进益生菌生长活性研究

研究豌豆蛋白酶解产物(PPH)对17株常见益生菌在普通液体培养基及脱脂乳培养基中生长的影响。比较这17株益生菌在含有PPH的MRS培养基和不含PPH的MRS培养基中的菌体密度、活菌数和发酵液pH值,结果发现添加4mg/mL的PPH,可显著改善干酪乳杆菌、保加利亚乳杆菌、嗜酸乳杆菌和双歧杆菌等益生菌在MRS培养基中的生长,其菌体密度提高10.78%～49.34%,活菌数提高1～3个数量级,发酵液的pH值显著降低;然而其对植物乳杆菌、鼠李糖乳杆菌和嗜热链球菌的生长无明显影响。比较这17株益生菌在含有PPH的10%脱脂乳培养基和不含PPH的10%脱脂乳培养基中的活菌数和pH值,结果发现这些菌在含有PPH的10%脱脂乳培养基中的生长均优于不含PPH的10%脱脂乳培养基中的生长, pH显著下降,经特定时间发酵后的活菌数显著提高。经24 h发酵,PPH对鼠李糖乳杆菌W119的促生长作用最强,能使其活菌数从4.23×108提高到7.47×1011,发酵液pH值从5.83降到4.90。综上所述,豌豆蛋白酶解产物可显著促进益生菌的生长,提高益生菌的存活率,缩短益生菌的生产时间。     

杜仲叶水提取物对植物乳杆菌体外益生特性影响

为明确杜仲叶水提取物对植物乳杆菌体外益生特性的影响,采用活菌计数、扫描电镜和气相色谱等方法探究不同浓度ELWE对植物乳杆菌生长曲线、产酸性能、形态和耐受性等的影响。结果表明,培养24 h后,试验组的活菌数均显著高于对照组;ELWE(80,320 mg/mL)使植物乳杆菌菌体更加饱满,且能显著提高其产乳酸能力,36 h时乳酸含量分别提高42.07%和111.64%。在胃液环境的胁迫下,80 mg/mL ELWE组的对数存活率达到87.77%(3 h),显著高于对照组（0%）;80 mg/mL ELWE可显著提高植物乳杆菌在热、Na Cl、胆盐和真空冷冻干燥胁迫环境下的活菌数,分别保持在5.67,8.16,7.65,7.78 lg CFU/mL。80 mg/mL ELWE对植物乳杆菌体外益生特性有积极影响。研究为ELWE在益生菌行业的应用提供理论参考。     

复合益生菌协同发酵葡萄汁菌种筛选与工艺优化

为增强葡萄汁的保健功能,以巨玫瑰葡萄为原料,选择21株益生菌对葡萄汁进行发酵,经过初筛和复筛,得到适宜葡萄汁发酵的植物乳杆菌21802和短乳杆菌6239,并将两株菌进行复配,以活菌数和感官评分为指标,对复合益生菌协同发酵葡萄汁工艺进行优化。结果表明,复合益生菌协同发酵葡萄汁最佳发酵工艺条件为:植物乳杆菌21802与短乳杆菌6239的菌种比例1:2,葡萄汁料水比2:1,接种量5%,发酵温度36 ℃,发酵时间60 h。此条件下发酵所得益生菌发酵葡萄汁的活菌数可达到8.98×109 CFU/mL,感官评分为91.1分。     

Optimisation of vacuum impregnation of blackcurrant‐infused apple cubes: application of response surface methodology

The response surface methodology was used to investigate the effects of blackcurrant concentrate level, vacuum pressure and time on the mass transfer and nutritional properties of vacuum‐impregnated apple cubes. There were higher water loss and weight reduction in the samples at the middle‐level vacuum pressure, but the other factors had no effect on these properties. The higher the vacuum pressure and time, the higher the solids gain of the samples. There was opposing results of the antioxidant capacity of the samples in the middle and high blackcurrant concentrate level and vacuum pressure when compared with the low blackcurrant concentrate level and high vacuum pressure. The middle blackcurrant concentrate level gave higher ascorbic acid content of the samples, while the middle vacuum pressure gave lower values. The optimised conditions for vacuum impregnation of the apple cubes were 18–20% blackcurrant concentrate level, 77–80 kPa vacuum pressure and 38–45 min vacuum time.     

Calcium fortification of vegetables by vacuum impregnation: Interactions with cellular matrix

Calcium fortification of vegetables by applying vacuum impregnation (VI) is an alternative in developing functional foods. Nevertheless, calcium ions can interact with the plant tissue, modifying its mechanical and vacuum impregnation responses. These effects were studied in eggplant, oyster mushroom and carrot samples. Sample VI was carried out with isotonic solutions containing (i) sucrose and calcium lactate and (ii) sucrose. From the analysis of sample impregnation and deformation levels, the slight influence of Ca presence on the impregnation behaviour of these products could be concluded. Nevertheless, mechanical behaviour of eggplant and carrot were notably affected by calcium, although no significant effects were observed in oyster mushroom (without pectin in their cell architecture). Energy dispersive X-ray microanalysis (EDXMA) in impregnated products showed that calcium impregnation occurs in the intercellular spaces of eggplant and oyster mushroom and in xylem of carrot.     

Natural colorant enrichment of apple tissue with black carrot concentrate using vacuum impregnation

Coloured apple discs containing black carrot concentrate (BCC), calcium lactate and lactic acid were formulated and produced as a new functional fresh fruit product using vacuum impregnation. Sensory test was conducted to select the most preferred impregnation formulation containing an addition of 0.0%, 0.4%, 0.8% and 1.2% BCC, 1.5%, 3.0% and 4.5% calcium lactate and 2.0%, 3.0% and 4.0% lactic acid. Results indicated that the formulation with the addition of 3% Ca‐lactate, 3% lactic acid and 0.8% BCC within 0.2 m mannitol solution was significantly preferred. The optimum vacuum pressure (211 mm Hg), vacuum time (3 min) and restoration time (20 min) according to highest colorant transfer, while the minimum cellular disruption occurs were estimated using response surface methodology. The use of Ca‐lactate and BCC contributed the treated apple to resemble untreated apple properties in terms of texture, total phenolic, total flavonoid contents and antioxidant capacity.     

Ways and Means for the Infusion of Bioactive Constituents in Solid Foods

The development and consumption of functional food, or foods that promote health not merely basic nutrition, is on rise. In recent years, industrial and consumer interests have focused on developing foods supplemented with bioactive constituents that provide greater physiological benefits. The direct addition of these components to liquid or fabricated solid foods has led to a wide range of new products appearing on the market. Osmotic dehydration, an operation in which food stuff is soaked in solution of low water activity, has been reported as a suitable technology for formulating new products because of the twofold effect that it has on food where it partially removes water and impregnates the food pieces (solid food matrix) with solutes from the osmotic solution. The article focuses on the impregnation of bioactive constituents having added advantage to human health such as antioxidants, minerals, vitamins, and probiotics. The infusion of enzymes and aroma also has been discussed. Application of ultrasound, vacuum, high pressure, and/or atmospheric impregnation techniques appears to be the feasible technologies for impregnation of solid food matrix for the incorporation of bioactive ingredients.     

青脆李益生菌饮品的发酵工艺优化及冷藏对其品质的影响

探索青脆李益生菌饮品适宜的发酵菌株、工艺参数及贮藏条件,为青脆李益生菌饮品开发提供解决方案。对嗜酸乳杆菌、植物乳杆菌、嗜热链球菌及其组合发酵的益生菌饮品感官评价、pH变化进行研究,确定适宜的发酵菌株组合;对其发酵适宜接种量、发酵温度、发酵时间工艺参数进行优化,优化发酵工艺参数;对4 ℃冷藏条件益生菌饮品可滴定酸、pH、可溶性固形物含量、还原糖含量及活菌落总数变化等进行研究,获得适宜的贮藏条件。结果显示:青脆李益生菌饮品适宜发酵菌株组合为植物乳杆菌、嗜热链球菌、嗜酸乳杆菌混合菌株1:1:1,发酵温度25 ℃、发酵时间44 h,接种量0.7‰。验证实验表明感官评分高达9.2。4 ℃冷藏益生菌饮品30 d,可滴定酸含量、pH、可溶性固形物含量、还原糖含量均基本保持稳定,且活菌落总数20 d达8.6×107 CFU·mL?1、30 d达2.0×106 CFU·mL?1,满足活性乳酸菌饮品要求,表明利用青脆李为原料研发益生菌饮品具有可操作性。     

真空浸渍对大头菜腌制过程中品质变化的影响

目的：研究真空浸渍工艺对腌制大头菜品质影响。方法：采用物性测试仪、色度计对大头菜的质构特性、色度进行测定,采用滴定法、干燥法、分光光度法等对大头菜的氯化钠、水分、总酸、氨基酸态氮、亚硝酸盐等理化指标进行测定,采用气相色谱法对大头菜的挥发性成分进行检测。结果显示,在腌制过程中,氯化钠、总酸、氨基酸态氮含量逐渐升高,脆度先升高后降低,同样处理时间内,真空浸渍组大头菜的各项指标明显比常压浸渍组大头菜的变化快;浸渍液含盐量20%的真空浸渍组大头菜各指标变化速度最快,腌制时间为90?d时,大头菜的各项理化指标、感官指标达到稳定;浸渍液含盐量20%真空浸渍90?d的大头菜与传统腌制工艺制备的大头菜挥发性成分不同,分别为27?种和31?种。综上,真空浸渍能提高大头菜腌制速度,缩短腌制时间,但需要联合微生物发酵等技术手段以保持传统大头菜的风味。     

Reduction in the pH of vegetables by vacuum impregnation: A study on pepper

A method to decrease pH value in pepper slices employing vacuum was studied. The effects of relaxation time (10, 15 and 30 min), vacuum level (200 and 400 mbar) and vacuum application period (2 and 5 min) were evaluated. Results showed that vacuum impregnation (VI) with lactic acid solution increased the acidification degree to a greater extent than processing carried out at atmospheric pressure. In particular, samples treated at 400 and 200 mbar and submitted to a relaxation period of 30 min, showed a reduction in pH ratio (RpH) from 0.929 to 0.894. Otherwise, samples submitted to conventional dipping at atmospheric pressure showed a RpH of 0.968. Vacuum level was found to be the most important variable influencing the variations in total mass and pH. Vacuum impregnation led to an increase in diffusion rate of hydrogen ions into the vegetable tissue due to the increase in contact area between acid solution and cells. Moreover, a direct correlation between pH reduction on the one hand, and vacuum application period and relaxation time on the other, was observed. Results proved that vacuum impregnation process is a useful technique to improve acidification treatments of vegetables.     

益生菌山药饮料发酵工艺优化及其冷藏稳定性

本研究以山药粉为原料,益生菌Lactobacillus plantarum P-8和Bifidobacterium lactis V9为发酵剂,对发酵工艺进行优化,以得到一种兼具山药营养价值与益生菌益生特性的益生菌山药饮料。通过单因素实验研究发酵时间、接种量、发酵温度对饮料中活菌数、滴定酸度以及pH的影响,在此基础上结合响应面分析获得发酵益生菌山药饮料最优发酵工艺参数,即接种量为 2×106 CFU/mL、发酵时间为19.1 h、发酵温度为37 ℃。在此条件下饮料活菌数为4.3×108 CFU/mL,滴定酸度为105.3 °T。对饮料在4 ℃下贮藏28 d,贮藏期内饮料活菌数稳定维持在108 CFU/mL,饮料组织状态良好、风味及口感稳定。     

真空醋渍黄瓜品质的介电检测

通过测量醋渍黄瓜的介电特性来衡量其品质并作为一种潜在的非损伤性评价手段。研究采用平行板电极测量了经过不同时间真空醋渍处理的黄瓜于100 kHz~12 MHz的介电特性,同时测量了反映醋渍黄瓜理化品质的参数,如酸度、盐度、亚硝酸盐含量、质构参数。研究结果表明,在整个频率区间,真空醋渍黄瓜的相对介电常数和介电损耗因子都随频率的增加而单调递减,真空醋渍时间与介电参数存在负相关关系。真空醋渍黄瓜的介电参数与盐分和亚硝酸盐含量存在着较好的相关性,然而介电参数与酸度、质构指标之间的相关性不明显。在2.26 MHz和12 MHz频率下,相对介电常数与盐分呈现出良好的线性关系,线性拟合方程的决定系数R2高达0.9813和0.9858;该研究为真空醋渍蔬菜快速检测仪器的开发提供了理论参考。