Fermentation of Cucumbers Brined with Calcium Chloride Instead of Sodium Chloride

ABSTRACT: Waste water containing high levels of NaCl from cucumber fermentation tank yards is a continuing problem for the pickled vegetable industry. A major reduction in waste salt could be achieved if NaCl were eliminated from the cucumber fermentation process. The objectives of this project were to ferment cucumbers in brine containing CaCl₂ as the only salt, to determine the course of fermentation metabolism in the absence of NaCl, and to compare firmness retention of cucumbers fermented in CaCl₂ brine during subsequent storage compared to cucumbers fermented in brines containing both NaCl and CaCl₂ at concentrations typically used in commercial fermentations. The major metabolite changes during fermentation without NaCl were conversion of sugars in the fresh cucumbers primarily to lactic acid which caused pH to decrease to less than 3.5. This is the same pattern that occurs when cucumbers are fermented with NaCl as the major brining salt. Lactic acid concentration and pH were stable during storage and there was no detectable production of propionic acid or butyric acid that would indicate growth of spoilage bacteria. Firmness retention in cucumbers fermented with 100 to 300 mM CaCl₂ during storage at a high temperature (45 °C) was not significantly different from that obtained in fermented cucumbers with 1.03 M NaCl and 40 mM CaCl₂. In closed jars, cucumber fermentations with and without NaCl in the fermentation brine were similar both in the chemical changes caused by the fermentative microorganisms and in the retention of firmness in the fermented cucumbers.     

Fermentation of Cucumbers Without Sodium Chloride

Cucumbers were successfully fermented and stored in the absence of sodium chloride (salt) under laboratory conditions, provided the fruit were blanched (3 min, 77°C) before brining in a calcium acetate buffer and the brine inoculated with Lactobacillus planturum. Bloater formation was prevented by blanching even when brines were not purged of CO₂. Firmness of cucumbers was similar in salt-free brines or those containing salt after 1 mo, but firmness of salt-free cucumbers was lower after storage for 12 mos. Under pilot-scale, commercial conditions, however, the cucumbers were severely bloated, and the firmness was unacceptable after storage for 7 mo, due apparently to Microbial recontamination after blanching.     

Effect of Calcium Chloride and Alum on Fermentation, Desalting, and Firmness Retention of Cucumber Pickles

The effects of CaCl₂ in cucumber pickle fermentation and storage brines on fermentation, desalting and retention of mesocarp firmness after processing were determined. Also, the influence of post-desalting treatments with alum and CaCl₂ on firmness of processed pickle was evaluated. Fermentation and desalting were unaffected by CaCl₂ treatment of fermentation brines. However, exposure of pickles to CaCl₂ during fermentation and brine storage substantially reduced softening after processing. Post-desalting treatment with alum and/or CaCl₂ of pickles not previously exposed to CaCl₂ also reduced softening. Retention of firmness was maximized in pickles processed from fermentation and storage brines containing CaCl₂ and treated with alum or CaCl₂ after desalting.     

Firmness Retention in Pickled Peppers as Affected by Calcium Chloride, Acetic Acid, and Pasteurization

Critical factors influencing firmness retention in pickled peppers were studied. The addition of CaCl, (0.2%, w/v, optimum) to whole, pickled‘Red Cherry’peppers increased firmness retention as determined by a puncture test using an Instron Universal Testing Machine. Pasteurization reduced firmness in the absence, but not in the presence, of added CaCl₂. CaCl₂ significantly (P ≤0.01) reduced softening during storage of‘Red Cherry’peppers at higher temperatures (36.7, 46.7°C), and resulted in a slight increase in firmness at 26.7°C. CaCI₂ did not significantly (P≥ 0.05) improve firmness retention in‘Jala-peno’peppers, but resulted in greater uniformity of firmness. CaCI, also improved firmness retention in pickled cucumbers. Firmness of unpasteurized peppers and cucumbers was not influenced significantly (P ≥0.05) by acetic acid concentrations of 2, 3 or 4%.     

高浓度CaCl2溶液对某些肌原纤维蛋白的作用研究

用0、100、200、300mmol/LCaCl2溶液处理肌球蛋白、肌动蛋白和肌原纤维,通过SDS-PAGE和免疫印迹电泳研究100、200、300mmol/L高浓度CaCl2溶液处理下肌球蛋白、肌动蛋白、α-肌动素和肌钙蛋白-T的蛋白降解情况。SDS-PAGE结果显示,肌球蛋白、肌动蛋白在100、200、300mmol/LCaCl2溶液处理下1、7d时的电泳结果与对照组相比没有显著差异。免疫电泳结果显示,100、200、300mmol/L高浓度CaCl2溶液处理后,α-肌动素和肌钙蛋白-T与对照组相比发生显著降解,随着浓度升高,降解程度加大,在300mmol/L浓度时,α-肌动素条带密度显著降低,肌钙蛋白-T也裂解为30kD以下的更小片段。     

Commercial Scale Cucumber Fermentations Brined with Calcium Chloride Instead of Sodium Chloride

Development of low salt cucumber fermentation processes present opportunities to reduce the amount of sodium chloride (NaCl) that reaches fresh water streams from industrial activities. The objective of this research was to translate cucumber fermentation brined with calcium chloride (CaCl₂) instead of NaCl to commercial scale production. Although CaCl₂ brined cucumber fermentations were stable in laboratory experiments, commercial scale trials using 6440 L open‐top tanks rapidly underwent secondary cucumber fermentation. It was understood that a limited air purging routine, use of a starter culture and addition of preservatives to the cover brine aids in achieving the desired complete cucumber fermentation. The modified process was used for subsequent commercial trials using 12490 and 28400 L open‐top tanks packed with variable size cucumbers and from multiple lots, and cover brines containing CaCl₂ and potassium sorbate to equilibrated concentrations of 100 and 6 mM, respectively. Lactobacillus plantarum LA0045 was inoculated to 10⁶ CFU/mL, and air purging was applied for two 2–3 h periods per day for the first 10 d of fermentation and one 2–3 h period per day between days 11 and 14. All fermentations were completed, as evidenced by the full conversion of sugars to lactic acid, decrease in pH to 3.0, and presented microbiological stability for a minimum of 21 d. This CaCl₂ process may be used to produce fermented cucumbers intended to be stored short term in a manner that reduces pollution and waste removal costs.     

Assuring Microbial and Textural Stability of Fermented Cucumbers by pH Adjustment and Sodium Benzoate Addition

Acidification of fermented cucumbers with HCl prevented utilization of lactic acid and resultant rise in brine pH (accompanied by formation of butyric, propionic and acetic acids, and n-propanol by spoilage bacteria) when they were stored at 0 or 4.4% NaCl. Firmness retention of the fermented cucumbers was reduced, however, if the brine pH were less than optimum pH 3.5, which assured microbial stability and acceptable firmness retention with 4.4% NaCl. At 0% salt, pH 3.0 insured microbial stability, but resulted in unacceptable firmness. Addition of 0.1% Na benzoate reduced the need to lower pH to assure microbial stability. Results indicated that pH control could be used to reduce the need for salt to insure stability of fermented cucumbers.     

不同菌种制备酱油大曲生产酶系特性及其耐盐性的比较

采用4株米曲霉菌种(j2、y2、x42、x72)与对照米曲霉菌株(沪酿3.042)制备大曲,探究其所产中性蛋白酶、酸性蛋白酶、α-淀粉酶以及糖化酶在盐浓度为0%、5%、10%、15%、20%下酶活力变化。实验结果表明,5株菌株所产酶系中,中性蛋白酶活随盐水浓度的增加显著(P<0.05)下降,酸性蛋白酶和糖化酶在5%盐浓度下活力显著下降(P<0.05),随后酶活力下降速率减慢,α-淀粉酶在5%的盐浓度下无显著下降(P>0.05),随后下降速率加快。此外,相同盐浓度下淀粉酶比蛋白酶更稳定,5株米曲霉菌株的α-淀粉酶和糖化酶在20%的盐浓度下残留率均达到50%。菌株y2、j2所产中性蛋白酶和菌株x72所产酸性蛋白酶的耐盐性优于对照菌株。     

Vacuum Infusion of Citrus Pectinmethylesterase and Calcium Effects on Firmness of Peaches

Vacuum infiltration of Majestic peaches (Prunus persica) for 1 hr with a solution of Marsh grapefruit pectinmethylesterase (PME) containing 100 mg/L CaCl₂ significantly increased firmness of canned peaches. Mean firmness of peaches infused 2 hr and thermally processed was 13.9 J/Kg as compared to 3.2 J/kg for noninfused, processed controls. The calcium content increased from 278 to 432 mg/kg during 2 hr infusion of blanched peaches. Specific activity of PME in peach halves increased more than 20 fold after infusion.     

斩拌方式和氯化钠浓度对白鲢鱼糜品质特性的影响

以冷冻白鲢鱼糜为原料,研究真空斩拌(-0.06 MPa)条件下氯化钠浓度对白鲢鱼糜质量特性的影响,以期为真空斩拌技术在鱼糜制品加工中的应用提供理论依据。与常压斩拌相比,真空斩拌后的鱼糜蛋白的表面疏水性显著增加(p0.05),二硫键含量降低(p0.05),气泡的数量减少、直径减小;鱼糜凝胶的破断力和破断距离增加(p0.05),持水性增加(p0.05),而白度值降低(p0.05)。在真空和常压斩拌条件下,随着氯化钠浓度的增加,斩拌后的鱼糜蛋白质的表面疏水性和二硫键含量显著增加(p0.05),起泡性显著增强;制备的鱼糜凝胶的破断力和破断距离,随着氯化钠浓度的增加而显著增加(p0.05),浓度超过1%后显著降低(p0.05),持水性随着氯化钠浓度的增加显著增加(p0.05)。常压斩拌条件下,鱼糜凝胶白度值随着氯化钠浓度的增加而显著增加(p0.05)。而在真空斩拌条件下白度值逐渐降低(p0.05)。     

Gelation of β-Lactoglobulin: Effects of Sodium Chloride and Calcium Chloride on the Rheological and Structural Properties of Gels

Heating β-lactoglobulin solutions at pH 8 causes an increase in viscosity, but self-supporting gels were not formed unless salts, such as sodium chloride or calcium chloride, were added. The rheological and textural properties and gel strength were markedly affected by salt concentration. Thus, gels of maximum compressive strength were obtained with sodium chloride and calcium chloride at concentrations of 200 and 10mM, respectively. Increasing the concentration of sodium chloride resulted in the formation of soft gels which released water easily. Calcium chloride strengthened β-lactoglobulin gels by forming crossbridges. However, above 10 mM it tended to enhance coagulation rather than gelation. This was confirmed by election microscopy of the gel matrix.     

氯化钠对面条品质影响的研究

氯化钠能明显影响到面团的流变学特性及成品面条的质构和蒸煮品质.随氯化钠添加量的增加,面条的质构指标均呈先增大后减小的趋势,面条表面亮度增大,最佳蒸煮时间逐渐减小.研究结果表明,当氯化钠添加量达到4%时,面条整体品质水平较为优秀.但当添加量过高时,氯化钠会阻碍面筋蛋白的充分水化,从而引起面条内部干燥,结构松散,最终导致面条品质的下降.     

Calcium Chloride and Potassium Sorbate Reduce Sodium Chloride used during Natural Cucumber Fermentation and Storage

Cucumber fermentation characteristics and pickle quality were evaluated in brines containing equilibrium concentrations of 0-0.4% CaCl₂, 0-0.4% potassium sorbate and 0-10% NaCl. Changes in brine pH and acidity, cucumber texture and color, coliforms, lactic acid and total bacteria, yeasts and molds were followed over time. Results indicated that cucumber spoilage would eventually take place if NaCl or potassium sorbate were not present in the brine. The presence of CaCl₂ helped maintain cucumber firmness. A synergistic action between NaCl, CaCl₂ and potassium sorbate was seen, which allowed good quality pickles to be produced when moderate amounts of all three components were present in the brine (5% NaCl, 0.2% CaCl₂, 0.2% potassium sorbate).     

NaCl和葡萄糖对抗性淀粉形成的影响

以高直链玉米淀粉为试材,分别研究了NaCl浓度和葡萄糖浓度对抗性淀粉形成的影响,发现当NaCl浓度提高到10%以上时,抗性淀粉得率从10.2%提高到16.5%。当NaCl浓度达50%时,抗性淀粉得率提高到17.1%,此后,即使NaCl浓度增加到60%,抗性淀粉得率也不再增大。当葡萄糖浓度从20%增加到60%,抗性淀粉得率从10.0%缓慢增加到14.2%,此后,即使葡萄糖浓度增加到70%,抗性淀粉得率仍维持在14.2%。显然,高浓度NaCl或葡萄糖能够促进抗性淀粉的形成,其原因可能是NaCl或葡萄糖降低了水分活度并且使直链淀粉分子更容易相互靠近、联结。     

Firmness of Canned Grapefruit Sections Improved with Calcium Lactate

Hand cut commercially produced grapefruit sections, packed in either juice or syrup, were treated with 0._-l-0.5% calcium lactate throughout the 1988–1989 season and monitored for changes in shear force resistance. Firmness of both juice and syrup control packs declined about 40% during the processing season. Calcium addition did not reverse seasonal softening but incrementally decreased loss of firmness during processing. Improvements in texture were independent of seasonal changes, and remained relatively constant throughout the season. Optimal levels of calcium lactate were 0.3–0.4% for juice packed sections and the highest level used (0.5%) for syrup packed sections. Maximum increases in firming due to calcium in juice and syrup packed sections were 38 and 50%, respectively.     

乳酸钙部分替代氯化钠对鸭肉干品质的影响

选用乳酸钙部分替代传统的钠盐,在钠盐使用总量1.5% 的前提上,按照氯化钠摩尔质量的20%、30%、40%、50% 设计乳酸钙的替代比,单因素试验观察不同替代比对鸭肉干色泽、质构、风味和水分活度的影响。结果表明,乳酸钙替代氯化钠可显著提高鸭肉干产品的硬度、咀嚼性、亮度L 值和黄度b 值,并显著降低鸭肉干的水分活度(P ＜ 0.05),有利于延长产品的货架期;但过量使用乳酸钙,会对鸭肉干的感官品质带来负面影响,适宜的替代比为20%～30%。因此,合理选择乳酸钙的替代比,将有利于降低传统钠盐的使用量。     

Influence of Microbial Growth on the Redox Potential of Fermented Cucumbers

ABSTRACT:  Commonly, pH measurements are used during the production of fermented cucumbers to indirectly monitor growth of lactic acid bacteria (LAB) and acid production. Redox potential (E_h) measurements, which are determined by the potential of an electron to reduce an acceptor, could serve as an alternative tool to monitor the progress of fermentation allowing the detection of the metabolic activity and/or growth of LAB and other microorganisms. Pasteurized and inoculated jars of cucumbers were observed to better understand how the E_h changes during the cucumber fermentation and how it could be used as a monitoring tool. Jars of diced, brined cucumbers were pasteurized and inoculated with microbes previously isolated from fermented cucumbers including Lactobacillus plantarum , Zygosaccharomyces globiformis , and Enterobacter aerogenes . Although an initial decrease in E_h was observed for all microorganisms, distinctive trends in E_h occurred when these organisms were inoculated. After a 2-wk fermentation period, the E_h (Ag/AgCl, 3 M KCl) in jars inoculated with L. plantarum , Z. globiformis , and E. aerogenes was at +453 ± 55, +104 ± 5, and –156 ± 73 mV, respectively. Cucumbers inoculated with a mixture of L. plantarum and Z. globiformis had a terminal E_h value of +202 ± 24 mV, which was between that found for the individual microorganisms. L. plantarum dominated the E_h trend when inoculated along with E. aerogenes with a final E_h of +411 ± 72 mV. The results showed that changes in E_h continued after pH measurements became stable. Thus E_h measurement can provide a tool to continuously monitor microbial growth during the course of cucumber fermentations.     

CaCl2和木瓜蛋白酶处理对羊肉品质的影响

研究不同浓度的CaCl2注射或不同质量浓度的木瓜蛋白酶浸泡处理对云岭黑山羊股二头肌pH值、肉色、蒸煮损失、肌原纤维小片化指数、胶原蛋白、肌浆蛋白和肌原纤维蛋白降解的影响。结果表明：CaCl2注射或木瓜蛋白酶浸泡处理显著提高了肌原纤维小片化指数;0h和6h时对照组出现极限pH值,分别为6.75和6.15,而CaCl2处理组或木瓜蛋白酶处理组到达极限pH值时间为2h和24h,极限pH值分别为 6.83、6.29和6.90、5.89,SDS-PAGE分析显示CaCl2和木瓜蛋白酶促使羊肉肌肉中的肌动蛋白、肌球蛋白和连接蛋白发生降解。在0.3mol/L CaCl2或0.002g/100mL木瓜蛋白酶处理时,处理组的肌原纤维小片化指数和胶原蛋白的含量达到最大,蒸煮损失最小,表现出最佳的嫩化效果。     

Firmness and Cell Wall Characteristics of Pasteurized Jalapeño Pepper Rings Affected by Calcium Chloride and Acetic Acid

Pepper rings packed in brine containing CaCl₂ were firmer, had higher bound calcium, chelator soluble pectin and pectin DE, and less water-soluble pectin (WSP) than peppers packed in brine containing no CaCl₂. Pepper rings packed in low acid brines (1% and 1.2% acetic acid) were firmer and had less WSP than those packed in high acid brine. Those samples (4% acetic acid) resulted in softening and pectin solubilization, but CaCl₂ resulted in less softening. Monosaccharide composition of cell walls was not affected by CaCl₂ or acetic acid. Firmness retention in CaCl₂ treated samples was probably due to greater association between calcium ions and pectic substances, which resisted acid hydrolysis.