香芋粉喷雾干燥工艺研究

我国香芋资源极为丰富,但开发程度远不及山药、甘薯、马铃薯等,所以对香芋加工工艺的研究对其潜在价值的开发具有重要意义。通过单因素试验考察了烫漂温度、烫漂时间、进风温度、进料速度及料液浓度对香芋粉喷雾干燥的影响。试验确定了香芋粉喷雾干燥的最佳工艺为:55℃烫漂10 min、进风温度为180℃、进料速度50 mL/min、料液浓度为0.1 g/mL。     

不同预处理方式对微波干燥哈密瓜品质的影响

研究不同的漂烫工艺(热水和水蒸汽)对哈密瓜微波干燥品质的影响,对比了不同的漂烫方式、温度和时间对哈密瓜品质的影响。结果表明:采用100℃水蒸汽漂烫2 min效果最佳。在此基础上,研究了柠檬酸和抗坏血酸对哈密瓜护色效果的影响,结果发现,柠檬酸具有较好的护色效果,综合感官评价提升明显,维生素C含量最高,为12.1 mg/100 g。     

降低蔬菜硝酸盐含量的食前处理方法

以小白菜、萝卜和四季豆为试材,研究了不同食前处理（清水浸泡、盐渍、漂烫）对蔬菜硝酸盐和维生素C（VitC）含量的影响。结果表明,清水浸泡和漂烫处理均可较大程度地降低蔬菜硝酸盐含量;盐渍处理硝酸盐含量下降不明显,其中萝卜经盐渍后硝酸盐含量反而升高;三种处理方式以漂烫0.5 min处理蔬菜VitC含量损失最小。     

速冻白芦笋嫩茎的生理生化变化

白芦笋嫩茎经过清洗、护色、烫漂、冷却等处理后,其生理生化发生了变化。清洗的水温５～７℃,白芦笋的多酚氧化酶和过氧化氢酶活性、呼吸强度和粗纤维含量均较低;护色中加入没食子酸丙酯和焦亚硫酸钠起护色和降低这两种酶的作用;烫漂的水温９０～９５℃、ｐＨ５．３～５．５、烫漂１．５～２．０分钟,白芦笋的两种酶钝化,外观乳白略透明,细菌总数、大肠菌群和大肠杆菌都达到卫生要求;烫漂后立即冷却才能降低细胞透性,达到外观的标准。     

速冻白芦笋嫩茎的生理生化变化

白芦笋嫩茎经过清洗、护色、烫漂、冷却等处理后，其生理生化发生了变化。清洗的水湿５－７℃，白芦笋的多酚氧化酶和过氧化氢酶活性、呼吸强度和粗纤维含量均较低。护色中加入没食子酸丙酯和焦亚硫酸钠起护色和降低这两种酶的作用；烫漂的水温９０－９５℃，ｐＨ５．３－５．５、烫漂１．５－２．０分钟，白芦笋的两种酶钝化，外观乳白略透明，细菌总数、大肠菌群和大肠杆菌都达到卫生要求；烫漂立即冷却才能降低细胞透性，达到外观     

烫漂和干制方法对蔬菜某些化学成分的影响

探讨了不同烫漂和干制方法对苋菜和荠菜中 β-胡萝卜素、抗坏血酸和叶绿素含量的影响。结果表明 ,用 93℃± 2℃的偏亚硫酸氢钾烫漂 1 min,以上化学成分保存率最高。低温干燥能最大限度地保存干制品中的 β-胡萝卜素、抗坏血酸和叶绿素     

黄芩叶茶生产过程中杀青工艺探究

黄芩叶茶是用黄芩的叶片制作而成的中药保健茶,黄芩叶中富含多种营养成分,具有较好的解热抗炎作用。目前民间黄芩叶茶的加工方式多种多样,致使其质量参差不齐,其中杀青工艺对产品的质量影响很大。目的:旨在探寻杀青工艺的最优条件,在保持其较好的外观和风味口感同时,也能充分保留其营养成分。方法:选取漂烫、蒸汽、微波三种杀青方式,以黄芩叶中过氧化物酶(Peroxidase, POD)活性,化学成分含量以及外观性状作为评价指标,在每一种杀青方式中筛选出各自最优的工艺参数,最后对经过最优工艺条件处理的三种杀青方式之间作比较,筛选出最好的杀青方式。结果:每种杀青方式筛选出的最优工艺条件分别为:1.漂烫杀青:95℃热水漂烫2 min。2.蒸汽杀青:摊放厚度2 cm,熏蒸3 min。3.微波杀青:摊放厚度3 cm,600 W微波输出功率下处理50 s。经化学成分含量比较,确定最佳杀青工艺为微波杀青。结论:良好的杀青工艺能够钝化酶活性,使青草气挥发,香气显露,叶质变软,有利于之后工序的开展以及产品质量的提升。     

不同处理条件对叶菜类蔬菜亚硝酸盐含量的影响

目的：探明在采用盐酸萘乙二胺可见分光光度法下,测定具有代表性的叶菜类蔬菜中的亚硝酸盐含量在不同前处理条件下的变化。方法：采用常温（25±2℃）、冷藏（4℃）、密封冷藏（4℃）3种不同保存方式测定亚硝酸盐含量随着时间的变化规律;食前采用自来水、食用碱浸泡、果蔬洗涤剂浸泡及漂烫4种前处理方法。结果：3种不同保存方式下,随着时间的延长,亚硝酸盐含量表现为密封冷藏＜冷藏＜常温。自来水浸泡20min、5%食用碱浸泡、果蔬浸泡5min及漂烫0.5min 4种前处理方法均在一定程度上降低了蔬菜的亚硝酸盐的含量,且效果较其他清洗的处理条件稳定、明显,亚硝酸盐降低较快。结论：叶菜类蔬菜的亚硝酸盐含量在不同的放置条件下,均随存放时间的延长而增加。不同的食前处理均能降低亚硝酸盐含量,但在漂烫0.5min时,亚硝酸盐含量降低最为明显。建议消费者在选择叶菜类蔬菜时,冷藏储存,合理洗涤,避免长期放置。     

花椒生物碱与精油的同步提取方法比较

以干花椒和新鲜漂烫处理的花椒为原料,采用三种方案进行花椒精油与生物碱同步提取,比较其精油及生物碱的得率。结果,三种方法提取的精油得率基本相同;花椒生物碱得率为微波干法提取干花椒精油后再用乙醇渗漉提取生物碱的方法最高,干花椒和漂烫鲜花椒生物碱得率分别为1.24%和1.34%,而传统水蒸气提取精油后取滤液及微波湿法提取法精油后取滤液的方法分别为0.54%和0.62%、0.56%和0.54%。得率差异明显,微波干法提取精油后用75%乙醇渗漉法提取生物碱的得率是另外两种方法的2.5倍左右。     

金花茶鲜叶的杀青技术研究

以金花茶(Camellia nitidissima C.W.Chi)鲜叶为原料,以金花茶叶中主要活性成分叶绿素、茶多酚、黄酮的含量为指标,比较和分析了不同方式(漂烫、蒸汽、微波)对金花茶鲜叶杀青影响,以获得金花茶叶的最佳杀青方式及杀青条件,为金花茶资源的充分开发利用提供参考。研究结果表明:漂烫杀青对金花茶鲜的叶绿素和茶多酚的破坏非常大,不利于活性成分的保留;蒸汽杀青对金花茶鲜叶中黄酮的含量影响较大,与其它2种杀青方式相比含量最低;而采用微波杀青的金花茶叶中各活性成分含量均为最高。其中微波火力为528 W杀青时间90 s处理的金花茶鲜叶的叶绿素含量为0.881 04 mg/g,茶多酚含量为6.9%,黄酮含量为7.12%,可作为金花茶鲜叶的最佳杀青条件。     

IMPACT OF MICROWAVE BLANCHING ON THE FLAVOR OF ROASTED PEANUTS

Microwave blanching of peanuts was proposed as an attractive alternative to traditional techniques of blanching, because of energy and time savings. However, the occurrence of a processing‐related off‐flavor has been reported. This study examined the effect of processing factors during microwave blanching on the MC and sensory characteristics of the peanuts. The peanuts reached a range of internal temperatures during microwave blanching treatments between 4 and 11 min. A total offnote attribute was introduced to the peanut lexicon and was used successfully to differentiate the effects of microwave treatments. The microwave‐associated off‐flavor was related (but not identical) to cardboardy/stale flavor, and was related inversely to the positive flavor attributes roasted peanutty, sweet aromatic and sweet taste. Peanuts reaching the highest internal temperatures and greatest moisture losses during blanching exhibited the most total offnote flavor; however, temperatures as high as 113C did not produce significantly increased total offnote intensity.     

营养型葛仙米果冻的制作工艺研究

研究营养型葛仙米果冻的制作工艺,为武陵山区葛仙米特色资源的开发提供新途径。将烫漂护色后的葛仙米打浆制得葛仙米汁,以葛仙米汁为主要原料,卡拉胶、魔芋胶为胶体基材,进行营养型葛仙米果冻生产工艺的研究。利用单因素试验和正交试验,通过感官评价和质构指标的综合分析,得到葛仙米果冻的最佳配方为:复合胶含量1%(m卡拉胶∶m魔芋胶=6∶4),柠檬酸含量0.3%,葛仙米汁含量30%,白糖含量14%和β-环糊精含量2%~4%。在此条件下制作的葛仙米果冻口感爽滑,绿色天然、酸甜适口、质地均匀,具有一定的保健功能。     

Structure-function studies on red pigment-concentrating hormone; the significance of the terminal residues

The significance of the terminal residues of the red pigment-concentrating hormone (RPCH: Glu-Leu-Asn-Phe-Ser-Pro-Gly-Trp-NH2) for its blanching effect on crustacean chromatophores has been investigated. The chemical synthesis of the following small analogues, starting from the C-terminal amino acid are described: Ac-Trp-NH2, Boc-Gly-Trp-NH2, Ac-Gly-Trp-NH2, Gly-Trp-NH2, Ac-Pro-Gly-Trp-NH2, Glu-Trp-NH2, Glu-Pro-Gly-Trp-NH2, Ac-Pro-Gly and Glu-Pro-Gly-NH2. Assay of the biological activity of the various synthetic compounds in the shrimp Leander adspersus has established that only the C-terminal tryptophan residue is indispensable for the blanching effect of the hormone, although elongation of the chain length improves its potency.     

Heat-stable enterotoxin produced by Shigella flexneri.

Filtrates and ultrasonics extracts of Shigella flexneri showed rapid permeability factor (PF) test and proved positive in suckling mice and ligated rabbit loop tests within 4 hr. Delayed PF was not detected and the rabbit loop dilatation test read after 18 to 24 hr, the mouse pad oedema reaction, the test for elongation effect of CHO cells were also negative. In the delayed PF test a strong "blanching" effect was observed. A filtrate of an Ent-Escherichia coli strain was positive only in the rapid PF test, while filtrate and ultrasonic extract prepared from the Ent+ E. coli strain showed a positive reaction in all tests for enterotoxins (ST and LT) including the rapid PF test. Ultrasonic extracts of a S. flexneri and an Ent- E. coli strain concentrated by freeze-drying were fractionated on Sephadex G-100 column. S. flexneri fractions of 60--70ml were positive for rapid PF, dilation capacity in suckling mice, and the blanching effect in the delayed PF test. No positive reaction was found in the delayed PF test and in CHO cell culture. Similar fractions of Ent- E. Coli carried substances responsible for the rapid PF and the blanching effect, but without suckling mice positivity.     

Microbiological characteristics of Pacific shrimp (Pandalus jordani).

Microorganisms associated with Pacific shrimp (Pandalus jordani) were isolated and identified. Those on the iced raw shrimp, which yielded an average count of 1.6 x 10(6), were predominantly Moraxella, Pseudomonas, Acinetobacter, Arthrobacter, and Flavobacterium-Cytophaga spp. The blanching and peeling reduced the microbial level to 3.3 x 10(4) and also selectively eliminated Moraxella spp. The microbial flora changed after each processing sequence, and the heat sensitivity and growth characteristics of the representative microbial groups suggested that the presence of Arthrobacter and Acinetobacter spp. in peeled shrimp may indicate inadequate cleaning of raw shrimp or a shorter blanching time. The presence of Moraxella and Flavobacterium-Cytophaga spp. would indicate the degree of secondary contamination, and the presence of Pseudomonas spp. would indicate the shelf-age of the processed shrimp.     

Optimization of low-cost drying methods to minimize lipid peroxidation in <Emphasis Type="Italic">Spirulina platensis</Emphasis> grown in the Philippines

Three low-cost drying methods (sun, solar, and draft oven) were optimized to produce Spirulina powder of optimal quality. Optimization in the pre-dehydration stage included the use of two antioxidants, α-tocopherol and tertiary-butyl hydroquinone (TBHQ), and two blanching methods, microwave and water bath, to inactivate enzymes. The efficiency of the pre-dehydration treatments at minimizing lipid peroxidation were evaluated in terms of the product’s oxidative stability using the thiobarbituric acid (TBA) test. The sample with the lowest TBA reactive substance (TBARS) value was considered the most stable. TBHQ was found to be significantly better than α-tocopherol in minimizing lipid peroxidation in blanched samples while α-tocopherol was better than TBHQ in unblanched samples. Microwave blanching exerted a greater stabilizing effect than water bath blanching. The combined effect of TBHQ and microwave blanching was found to be the most effective pre-dehydration treatment for minimizing lipid peroxidation in drying Spirulina. Among the three low-cost optimized drying methods, sun-drying produced a dried product with the lowest TBARS value (0.472 mg malondialdehyde.kg⁻¹), which was closest to that of the spray-dried (control) sample (0.434 mg MDA.kg⁻¹). Draft oven and solar drying produced dried products with the same average TBARS value (0.56 mg MDA.kg⁻¹). Sun-drying, when optimized, produced a dried product that was almost as stable as the spray-dried product. Presented at the 6th Meeting of the Asian Pacific Society of Applied Phycology, Manila, Philippines     

Preventive effect of Ligularia fischeri on inhibition of nitric oxide in lipopolysaccharide-stimulated RAW 264.7 macrophages depending on cooking method

Background

Ligularia fischeri (common name Gomchwi) is known for its pharmaceutical properties and used in the treatment of jaundice, scarlet-fever, rheumatoidal arthritis, and hepatic diseases; however, little is known about its anti-inflammatory effect. In this study the influence of blanching and pan-frying on the anti-inflammatory activity of Ligularia fischeri (LF) was evaluated.

Results

Fresh LF and cooked LF showed no significant effect on the viability of macrophages after 24 h incubation. Fresh LF was found to be the most potent inhibitor of nitric oxide (NO) production at 100 μg/ml, while pan-fried LF showed little inhibitory effect on lipoloysaccharide (LPS) stimulated murine machrophage RAW264.7 cells. In contrast with its effect on NO production, pan-fried LF showed significant attenuation of the expression of inducible nitiric oxide synthase (iNOS) compared with fresh LF. In the cooking method of LF, PGE₂ production was not affected in the LPS-induced RAW 264.7 cells. In LPS-induced RAW 264.7 cells, pretreatment by fresh and cooked LF increased COX2 mRNA expression. The 3-O-caffeoylquinic acid content of blanching and pan-frying LF increased by 4.92 and 9.7 fold with blanching and pan-frying respectively in comparison with uncooked LF.

Conclusions

Regardless of the cooking method, Ligularia fischeri exhibited potent inhibition of NO production through expression of iNOS in LPS-induced RAW264.7 cells.     

Ultrastructure-function correlative studies for cardiac cryopreservation. V. Absence of a correlation between electrolyte toxicity and cryoinjury in the slowly frozen,cryoprotected rat heart

Hearts were frozen to ?17 °C in the initial presence of 2.1 m DMSO. Attempts were made to prevent or minimize the consequences of an osmotic shock based on Lovelock's classical hypothesis of freezing injury. Substitution of mannitol or potassium for NaCl before freezing did not improve the results, nor did perfusion of thawed hearts with hyperosmotic perfusate. It was found that freezing and thawing resulted in a significant attenuation of coronary flow and that, as a result of this, DMSO was apparently retained within the heart after thawing. DMSO was also difficult to remove at 30 °C in the absence of prior freezing and caused a significant drop in coronary flow upon institution of DMSO washout with balanced salt solution. The blanching of freezing and thawing was also seen, in milder form, in nonfrozen hearts. For both frozen-thawed and nonfrozen hearts, the blanching was associated with DMSO washout with balanced salt solution. Flow was improved by perfusion with hyperosmotic perfusate in both nonfrozen and in frozen-thawed hearts, but the improvement was largely temporary. Evidence from earlier studies indicates that electrolyte concentrations during freezing cannot be correlated with cardiac cryoinjury, in support of the present findings. It is suggested instead that cryoprotectant toxicity may be the chief agent of injury under the conditions studied.