鲜切雪莲果防褐绿变工艺研究

以雪莲果为试材,研究鲜切雪莲果防褐绿变的工艺.实验中比较了不同护色处理方法的护色效果,采用正交实验筛选出鲜切雪莲果的最佳组合护色条件,雪莲果最优组合防褐绿变的工艺为0.1%CaCl2,0.15%柠檬酸,浸泡30min,在.21℃下冻藏7d,未见褐变和绿变.     

鲜切雪莲果护色保鲜工艺的研究

以雪莲果为试材,研究鲜切雪莲果防酶促褐变的工艺.实验中将物理方法和化学方法结合起来,采用正交实验筛选出鲜切雪莲果的最佳组合护色剂,从而确定雪莲果最优组合防褐变的工艺.结果表明:抗坏血酸、柠檬酸、EDTA-Na2和NaC1都有抑制褐变的效果,但组合抑制剂的护色效果比单元抑制剂好.且最佳组合护色剂为:0.15%抗坏血酸+O.10%柠檬酸+0.05%EDTA-Na2+1.5%NaC1.     

低糖雪莲果果脯的研制

以雪莲果为原料,对其果脯加工中的硬化、护色、渗糖、干燥等工艺条件进行了实验研究.结果表明,低糖雪莲果果脯加工的最佳工艺条件为:热烫90℃、3min;用3%葡萄糖酸内酯、0.15%的抗坏血酸溶液硬化护色6h;填充剂选择0.4%的低甲氧基果胶+0.2%的魔芋精粉;渗糖工艺采用真空渗糖.糖液浓度为50%.真空度0.075MPa,保持2h;于55℃下干燥24h,在此工艺条件下生产出了色、香、味俱佳,形态饱满,透明的低糖雪莲果果脯.     

鲜切砂梨加工技术的研究

采用抗坏血酸法与O3、稳定态ClO2等分别对鲜切砂梨进行杀菌和护色处理，并研究了不同温度条件下对鲜切梨品质的影响。研究结果表明：稳定态ClO2和O3对鲜切梨均具有较显著的杀菌效果，并对鲜切梨颜色保持具有一定的作用。研究表明：采用柠檬酸与抗坏血酸共同处理对鲜切梨颜色保持具有更为显著的效果；采用低温配合可增强O3杀菌效果和抗坏血酸护色作用。鲜切梨加工的最佳工艺参数利用0．2％的柠檬酸和0．2％抗坏血酸浸渍处理鲜切梨，去除表面水分后经臭氧杀菌30～45min；包装好后在温度为0～10℃进行贮藏，可保持其一周品质不坏。     

搅拌型仙人掌酸奶的研制

本试验将处理过的仙人掌切分成2×2mm颗粒,添加到酸奶中,研制成保健型饮料—搅拌型仙人掌酸奶。通过试验,仙人掌颗粒的最佳添加量为5％。仙人掌的护色可采取采用85～90℃下热烫1min,热烫后采用0.05％的抗坏血酸与0.05％柠檬酸护色。     

雪莲果、胡萝卜复合果酱的研制

以雪莲果、胡萝卜为主要原料,对雪莲果、胡萝卜复合果酱的配方,雪莲果原浆的护色,增稠剂的使用进行了研究。结果表明:100℃条件下热烫1 min,并添加抗坏血酸0.1%、柠檬酸0.3%调整雪莲果原浆pH值为4.0,可以有效的阻止褐变的发生;复合果酱的最佳配方为:雪莲果和胡萝卜比为1.0∶0.5,白砂糖40%,pH值3.0,浓缩时间20 min,琼脂0.2%,魔芋胶0.2%。得到一种可溶性固形物含量约45%、营养强化、风味独特的新型果酱。     

雪莲果乳酸菌发酵饮料的研制

以雪莲果为原料、保加利亚乳杆菌为菌种开发研制雪莲果乳酸菌发酵饮料,确定其最佳发酵条件和口感稳定性的工艺配方。结果表明：100℃条件下热烫1min,并添加抗坏血酸调整果汁pH 值为4.0～4.5,可以有效的阻止绿变的发生。最佳发酵工艺条件：雪莲果原汁添加量60ml、蔗糖添加量4g、奶粉添加量4g、接种量10%、发酵温度41℃;发酵饮料调配最佳配方：在100ml 雪莲果原汁的乳酸菌发酵液中添加蔗糖4g、黄原胶0.2g。     

鲜切荸荠的护色工艺研究

以新鲜荸荠为原料,结合单因素实验和正交实验,根据褐变度研究酸液烫漂和护色剂浸泡对荸荠护色效果的影响,筛选出鲜切荸荠的最佳护色组合。结果表明,酸液漂烫和护色剂浸泡对鲜切荸荠都具有较好的护色效果。鲜切荸荠的最佳漂烫工艺条件为70℃下0.3%柠檬酸溶液中漂烫90 s;最佳护色工艺条件是将漂烫过的荸荠浸入1.0%氯化钙溶液+0.15%亚硫酸氢钠溶液+0.3%植酸溶液中浸泡20 min。     

鲜切雪莲果护色效果的研究

研究不同褐变抑制剂对鲜切雪莲果护色效果,通过正交试验并运用多指标试验设计综合加权评分法对多种抑制剂护色效果的进行综合选优.试验结果表明:采用0.5％柠檬酸+0.5％抗坏血酸+0.05‰焦亚硫酸钠浸泡10min的复合处理,试验综合加权评分值为97.6414.雪莲果的PPO活性为0.007、褐变度为3.62、感官品质为7,在10d内抑制褐变效果最好.     

红薯饮料护色工艺研究

本试验研究了红薯饮料生产工艺环节中不同护色剂的护色效果,并确定了最佳护色工艺。结果表明：比较三种单一护色荆的护色效果,0．5％Vc〉1％柠檬酸〉0．5％Na2SO3;最佳护色工艺为：0.3％抗坏血酸,0．6％的柠檬酸,浸泡15min。     

雪莲薯原汁加工工艺及其对双歧杆菌生长的影响

为研究雪莲薯原汁的加工工艺及其对双歧杆菌生长的影响,在漂烫工艺中,选用100℃、2.5min 的工艺条件,通过正交试验确定纤维素酶酶解的最佳工艺条件为纤维素酶用量0.08%(m/m)、pH5、温度50℃、酶解时间45min。利用果胶酶提高雪莲薯汁的澄清度,果胶酶用量为0.14%。雪莲薯原汁可有效促进双歧杆菌的生长,10%(m/m)添加量可使双歧杆菌生长量增加53%,20%(m/m)添加量对大肠杆菌有一定抑制作用。     

Lactobionic acid as a suitable food preservative for yacon juice

Yacon root is known for its antioxidant, prebiotic and insulin modulator benefits. However, like the root, yacon juice exhibits rapid enzymatic browning, requiring treatments such as acidification. Lactobionic acid (LBA) is a promising food ingredient, which contains not only preservative but also nutritional properties. The first goal of this study was to evaluate the influence of combined treatments (blanching, acid pretreatment) and LBA on refrigerated yacon juice (8 °C; 48 h). The analysis of pH, antioxidants, total polyphenols and color, were used to select the optimal combined conditions, which were steam blanching (10 min) + LBA 1%. Secondly, the LBA was compared with citric, malic, tartaric, and ascorbic acids (at 1% levels), where the kinetics of polyphenol oxidases were determined in refrigerated storage of the juice at 8 °C for 48 h. Results showed that LBA, malic and tartaric acids maintained the color of yacon juice and preserved bioactive compounds. LBA and malic acid prevented enzymatic browning with PPO reductions of 80.4% and 79.4%, respectively. This was the first time that LBA has been tested in a refrigerated juice showing significant potential for preservation of color and bioactive compounds in food products.     

超声波辅助漂烫预处理对太阳能-热泵联合干燥南瓜片品质的影响

研究超声波辅助漂烫预处理方法对太阳能-热泵联合干燥南瓜片品质的影响,以超声波温度、功率、频率和处理时间为单因素,研究其对干燥南瓜片色差、硬度、β-胡萝卜素及抗坏血酸含量的影响。通过正交优化分析获得最优工艺条件,并与传统漂烫预处理进行干燥南瓜品质的对比实验。结果表明,在超声波温度70 ℃、超声波功率为300 W、超声波频率为35 kHz、超声波处理时间为3 min条件下,干燥处理对南瓜片的颜色及营养物质含量的影响最小,色差值为9.95,相比于传统热烫的预处理方法减少61.64%;硬度值为36.61 N;抗坏血酸含量为13.00 mg/100 g,较传统热烫提高41.38%。因此,相比于传统热烫的预处理方法优势依然明显。证明超声波这一物理手段可显著减少南瓜热处理时色泽变化及抗坏血酸等营养物质的流失,超声波辅助漂烫预处理手段可用于南瓜片干燥加工中。     

香菇预制菜制备工艺优化

为获得方便、健康的香菇预制菜，本研究以活性物质多糖为营养指标，以色泽为外观指标，以质构和风味为品质指标，对制备香菇预制菜的复水、漂烫、护色、杀菌等工艺和条件进行优化。结果表明，通过复水-漂烫条件联合优化，获得最优复水-漂烫条件为：室温复水50 min，漂烫3 min，此时多糖损失率最低，为24.31%±3.03%，香菇硬度较低，咀嚼性适中。以色差值和可表征美拉德反应程度的A₂₉₄和A₄₂₀为评价指标，通过正交优化获得切片后香菇的复合护色剂为柠檬酸12 g/L，抗坏血酸0.8 g/L,L-半胱氨酸2.0 g/L，进一步优化确定护色时间为20 min，此时ΔE为17.00±0.08，色泽综合评分为10.295±0.190。最后通过比较高压杀菌、常压杀菌和辐照杀菌对香菇色泽和风味的影响，确定预制调理香菇的最优杀菌方式为60Co-γ射线辐照冷杀菌。本研究优化的香菇预制菜制备工艺简单、生产周期短，能较好的保留香菇原有的营养价值与独特的风味，适合大规模工业化生产。     

干制和保藏过程中枸杞β-胡萝卜素保存率的研究

研究了枸杞脱水干制过程中热烫时间和热烫温度、预处理、以及干制工艺条件对β－胡萝卜素保存率的影响，并对干制工艺条件进行了优化组合，优化组合条件如下：枸杞鲜果蒸汽热烫２分钟，用０．３％Ｎａ２ＳＯ３＋０．０３％Ｖｃ＋０．０４％ＥＤＴＡ－Ｎａ２溶液预处理１ｈ，在５０℃２０ｈ、６０℃１２ｈ、６５℃１１ｈ的干制工艺条件下进行脱水干制，β－胡萝卜素保存率可达８９．１％。此外，还探讨了包装材料颜色及保藏温度对枸杞干果β－胡萝卜素保存率的影响，结果表明：保藏温度对β－胡萝卜素保存率无显著影响，而包装材料的颜色对β－胡萝卜素保存率有显著的影响。     

超声波辅热联合抗坏血酸对胡萝卜钝酶效果的影响

利用超声波辅热联合抗坏血酸(ultrasonic-assisted blanching combined with ascorbic acid,UBA)的方法对胡萝卜进行预处理。以过氧化物酶和多酚氧化酶为灭酶指标,通过单因素试验以及响应面分析法得出UBA预处理的最佳作用参数;比较UBA预处理、漂烫预处理以及抗坏血酸浸泡预处理对胡萝卜品质的影响。预处理工艺优化结果为超声波功率强度0.29 W/m L、作用时间3 min、作用温度60℃、抗坏血酸质量分数1%;相较于其他的预处理方法,UBA预处理在保证灭酶效果的基础上不仅能显著提高胡萝卜样品中的VC含量,还能最大程度地维持胡萝卜细胞的原有结构,是一种温和且高效的预处理方式。     

EFFECT of LOW TEMPERATURE BLANCHING, CYSTEINE-HCi, N-ACETYL-L-CYSTEINE, Na METABISULPHITE and DRYING TEMPERATURES ON the FIRMNESS and NUTRIENT CONTENT of DRIED CARROTS

Low temperature long time (LTLT) blanching (70C for 20 min) together with calcium treatment can be used to significantly improve the texture of rehydrated dried carrots when compared to high temperature short time (HTST) blanching (100C for 3 min). LTLT blanching allows pectin methyl esterase to deesterify pectin which can then react with calcium to form salt bridges. 0.3% L-cysteine-HCl was found to be most effective in preventing ascorbic acid loss and obtaining a product with the highest rehydration ability, compared to pretreatments with 0.3% N-acetyl-L-cysteine and 0.1% sodium metabisulphite. On the other hand 0.1% sodium metabisulphite was most effective in preserving the carotenoids content of dried carrots. Ascorbic acid and rehydration ability were more adversely affected by long drying time than high drying temperature, while carotenoids were more sensitive to high drying temperature than drying time. Hence, 60C drying temperature was good for ascorbic acid and rehydration ability, while 40C drying temperature was good for carotenoid and color of dried carrots.     

EFFECTS OF BLANCHING, CHEMICAL TREATMENTS AND FREEZING METHODS ON QUALITY OF FREEZE-DRIED MUSHROOMS

SUMMARY –Mushrooms, Agaricus bisporus, were cut into slices about 5 mm thick. The polyphenoloxidase activity in the sliced mushrooms was inhibited by: (a) dipping in sodium metabisulfite solution containing 200 ppm SO₂; (b) dipping in 2% NaCl solution; and (c) blanching in boiling water for 2 min followed by evaporative cooling. The products were frozen with Freon-12 at –22°F for 60 sec. The frozen mushrooms were dried to 3% moisture in a Stokes freeze drier and sealed under vacuum in No. 2–1/2 cans. The freeze-dried product made by the Freon-dipping process was better in quality and firmer in texture than that made by the slow-freezing process. Blanching the fresh mushrooms in boiling water for 2 min prior to freezing results in a lighter color in the freeze-dried products after rehydration. However, the product was less attractive in flavor and texture. The blanching process caused considerable loss of water-soluble solids and ascorbic acid. The effects of processing variables on the chemical, physical and organoleptic quality of the rehydrated products are presented.     

鱼香肉丝工业化生产胡萝卜护色工艺优化

为防止鱼香肉丝中胡萝卜褐变,尽量维持胡萝卜明亮的颜色,该研究以色差值和感官评分为考查指标,比较了乙二胺四乙酸二钠(EDTA-2Na)、L-抗坏血酸(V_C)、异抗坏血酸钠和柠檬酸对鱼香肉丝中胡萝卜的护色效果;研究了其质量分数、浸泡时间和温度对胡萝卜的护色效果。通过单因素与正交试验结合确立最适合胡萝卜的护色剂复配配方为：柠檬酸0.3%,乙二胺四乙酸二钠(EDTA-2Na)0.4%,L-抗坏血酸(V_C)0.3%,异抗坏血酸钠0.2%。其中,柠檬酸浓度对护色效果影响最大,异抗坏血酸钠影响最小;护色条件为25℃、30 min;在此护色条件下处理的胡萝卜的色差变化最小(ΔE值为4.19)。将胡萝卜与护色液以重量比1:4的比例在25℃环境下浸泡30 min,后通过漂烫、冷却、脱水,再制成鱼香肉丝,其中的胡萝卜颜色和品质保持较好。该研究结果可为鱼香肉丝的工业化生产提供理论基础。