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 Thermal Sterilization on the Selected Quality Attributes of Sweet and Sour Carp

In this study, a traditional Chinese dish, a ready-to-eat sweet and sour carp was developed. The effects of sterilization temperature (110, 115, 121, and 130°C) on the selected properties, including heat penetration characteristics, as well as rheological, instrumental color, texture, and sensory attributes, were investigated at the same lethality value (F₀) of 4.5 min. The results showed that the heat penetration parameters of cooking value (C-value) and the ratio of C-value to F₀ value (C-value/F₀) exhibited an inverse relationship with processing temperature. The color and rheological properties of the sauce and the texture of the fish sterilized at 130°C were better preserved compared to those sterilized at other temperatures. The sensory attributes of the product sterilized at 130°C scored highest among the final products sterilized at the four temperatures. This study suggested that short-time sterilization at a high temperature can minimize the negative thermal impact on sweet and sour carp product, which would be feasible in the practical production.     

热烫处理对罐藏蔬菜的质构和颜色的影响

１１种经过选择的蔬菜采用常规工艺加工但对热烫条件加以修改，然后测定杀菌后的蔬菜样品的质构。试验结果表明，低温长时间热烫可增加７种罐藏蔬菜，即胡萝卜、苣荬菜、甜菜根、韭葱、青刀豆、洋葱和白卷心菜的坚实度，其中４种罐藏蔬菜即胡萝卜、苣荬菜、韭葱和青刀豆的质构可有较大程度的改善。在此基础上选择青刀豆和苣荬菜作深入研究。方差分析表明，在添加Ｃａ￣（２＋）和Ｚｎ￣（２＋）的热汤水中进行低温长时间热烫处理将显著影响罐藏青刀豆和苣荬菜的质构、颜色。对热烫条件的优化可同时改善罐藏青刀豆和苣荬菜的质构和颜色。     

Improving textural quality in frozen jalapeño pepper by low temperature blanching in calcium chloride solution

The effects of low temperature blanching in calcium chloride solution of jalapeño peppers prior to freezing, on firmness retention, pH, methanol, colour and calcium ions of the product, were evaluated by response surface methodology. Texture, methanol content and pH were affected by all of the variables studied (P = 0.05). The optimum response was obtained at temperatures of 63.3–66 °C, calcium chloride concentrations of 0.17–0.21 m , immersion time of 11.6–14.4 min, with a holding time after blanching of 56.6–66.1 min. Microscopic evaluation of the thawed pepper showed that blanching in CaCl₂ solution provided a protective effect in maintaining cell wall integrity.     

The effect of storage temperature and time on the consistency and color of sterilized processed cheese

The effect of sterilization (117 °C for 20 min) on the color and consistency of processed cheeses was evaluated. The sterilization resulted in a darker shade (darker color) and increased firmness and elasticity of processed cheeses (P < 0.05). During the storage period (24 months) of sterilized processed cheeses, their color as well as consistency changed depending on the temperature tested (8 and 23 °C). The color change of sterilized processed cheeses was more significant at a higher storage temperature (23 °C) in comparison with the products kept at cold storage temperature (8 °C) (P < 0.05). The firmness of sterilized processed cheeses stored at 8 °C increased during the 24 months. The rise in firmness achieved in the products stored at 23 °C was followed by its decrease in the second year of storage.     

Fermentation of Cucumbers in Anaerobic Tanks

A procedure was developed and tested for fermentation of cucumbers at low concentrations of NaCl in experimental, anaerobic tanks. The procedure included washing of the cucumbers, use of a buffered cover brine composed of 0.045M calcium acetate, sodium chloride to equilibrate at 2.7% or 4.6%, Lactobacillus plantarum culture, and N₂ purging to remove dissolved CO₂. The fermentations were predominantly homofermentative, lactic acid accounting for 95% of the cucumber sugars fermented. Firmness retention of the fermented cucumbers during storage for 1 year was improved by heating packaged products to 69°C before storage, but firmness retention was acceptable in un-heated products.     

APPLICATION OF LOW TEMPERATURE HEAT TREATMENTS BEFORE RETORTING IMPROVES THE QUALITY OF CANNED POTATOES

Low temperature heat treatments applied to potatoes (cv Atlantic, Snowden, and Pike) prior to retorting were evaluated for their effect on sloughing in canned potatoes. Blanching in water for 30 min at 60 - 77C before retorting decreased potato breakage, brine turbidity, and brine soluble solids without adversely affecting firmness or color. Low temperature blanching was only effective when potatoes were retorted in CaCl₂ (0.1 %) brine solutions. Sloughing was also decreased by a hot-fill and hold process that utilized brine fill temperatures of 77 − 93C followed by a 30 min hold in CaCl₂ (0.1 %) brine before commercial sterilization. The hot-fill and hold method for control of sloughing in canned potatoes is an improvement over current methods because it eliminates the need for a blanching step and requires only minimal changes in equipment or product flow.     

Effect of temperature, pressure and calcium soaking pre-treatments and pressure shift freezing on the texture and texture evolution of frozen green bell peppers (Capsicum annuum)

The firmness of green bell pepper (Capsicum annuum) was studied under different processing conditions. Thermal texture degradation kinetics of pepper tissue between 75 and 95 °C could be accurately described by a fractional conversion model. The firmness of pre-processed pepper increased when the samples were submitted to several heat, pressure, and combinations of heat/pressure and calcium soaking pre-treatments. Pre-heating at 55 °C during 60 min and mild heat/high-pressure treatments (200 MPa at 25 °C, 15 min) yielded the best results, which were further improved when combined with calcium soaking. These pre-treatments significantly slowed down thermal texture degradation of pepper at 90 °C, a typical temperature used for pepper blanching prior to freezing. The above-mentioned pre-treated samples showed a significant reduction in firmness when frozen by regular freezing at 0.1 MPa. The same samples showed no changes in firmness when frozen by high-pressure shift freezing at 200 MPa. When freezing was carried out by high-pressure shift and after frozen storage (−18 °C) for 2.5 months, pressure pre-treated pepper showed a better retention of texture than thermal pre-treated pepper.     

Ribonucleosides: Chemical parameters for controlling the heat treatment of milk

From experimental findings concerning changes in the contents of ribonucleosides - which belong to the group of minor milk constituents - in heat-treated milk it can be concluded that the concentrations of cytidine, guanosine and inosine present in raw milk show a multifold increase in milk which has been subjected to thermization and holder pasteurization, whereas the adenosine level decreases. On the other hand, these enzyme- (e.g. adenosine deaminase, alkaline phosphatase) catalysed changes in the content of unmodified ribonucleosides in milk are not observed in milk samples after short- and long-time pasteurization, high temperature pasteurization, ultra-high heating and sterilization. The changes in milk ribonucleoside contents found in these heating regions are mainly attributable to the catalytic activity of the milk enzymes in the course of the heating-up phase. During short- and long-time-, as well as high temperature pasteurization i.e. in the whole pasteurization region, changes in the nucleoside levels correlating with processing temperature and holding time were not observed since in these heating regions milk enzymes, such as adenosine deaminase and alkaline phosphatase, are inactivated. Hence, in the whole region of pasteurization neither enzyme-induced degradation- and conversion reactions nor thermally induced chemical degradation reactions take place with respect to unmodified ribonucleosides. However, with sterilization values exceeding F₀ = 30 min thermally induced hydrolytic effects are observed in UHT milk samples which lead in particular to an increase in adenosine contents. Comparable observations were made as regards cytidine, guanosine, inosine and adenosine contents in sterilized milk samples. Summing up, it can be concluded that from the viewpoint of dairy technology cytidine, guanosine and mainly inosine can be taken into account as chemical parameters for detecting thermization and, in particular, holder pasteurization. For characterizing heat treatment in the region of pasteurization, high temperature pasteurization, UHT heating and sterilization unmodified ribonucleosides of milk appear to be unsuited. The studies on the Dimroth-rearrangement under heating conditions of thermization and holder pasteurization, as well as short-, long-time- and high-temperature pasteurization, ultra-high heating and sterilization have shown that N⁶-methyladenosine, which is the resulting product of the rearrangement, is suited to be used as chemical parameter for controlling milk heat-treatment under time-temperature conditions with sterilization values (F₀) lying between ≈0.4 and 22 min. N⁶-methyladenosine is, thus, suited to be used as a chemical parameter for detecting heat treatment in the upper range of high temperature pasteurization, the whole range of UHT heating and the lower range of sterilization (as normally applied in dairies). From the viewpoint of dairy technology N⁶-methyladenosine is, thus, suited to be used as a further chemical parameter mainly for characterizing the upper range of UHT heating and the lower range of sterilization of heat-treated milk.     

Control of Spoilage of Canned Mushrooms Inoculated with Clostridium sporogenes PA3679 Spores by Acid-Blanching and EDTA

A new process involving blanching in 0.05M citric acid and addition of 200 ppm CaNa₂EDTA in the canning brine (ABC) was compared to the standard commercial method (SCM) for control of spoilage of canned mushrooms inoculated with C. sporogenes PA3679 spores. Fresh mushrooms were uniformly inoculated by vacuum hydration in spore suspensions. Compared to the SCM, the ABC process reduced the potential number of nonsterile units per million cans at F_o 10 from 14.8 to 2.1. At F_o 8 and 10, the ABC process reduced spoilage of the canned products from 100 to 68.1% and 89.3 to 28.7%, respectively, compared to the SCM.     

Structural and physical properties of dried Anaheim chilli peppers modified by low‐temperature blanching

The effect of low‐temperature blanching and drying processes on the ultrastructural and physical properties of Anaheim chilli pepper was studied and optimum conditions to provide a final product with maximum firmness were determined. Lots of Anaheim pepper were blanched in water for 4 min at 48, 55, 65, 75 and 82 °C and maintained for hold times of 35, 45, 60, 75 and 85 min, blanched again for 4 min at 96 °C and dehydrated at 53, 60, 70, 80 and 87 °C. After treatment the samples were rehydrated in water at 30 °C. Rehydration ratio, texture and structural changes were evaluated. Optimisation used a second‐order rotatable central composite design. Texture and rehydration ratio were affected by blanching temperature and the interaction of blanching temperature with hold time (p ≤ 0.05); drying temperature did not show a significant effect. The best results, ie those which gave greatest firmness, were obtained by blanching at 64 °C for 4 min, holding for 55 min after blanching, followed by a second blanching at 96 °C for 4 min and then drying at 70 °C. Evaluation of the rehydrated dried pepper by microscopy showed that low‐temperature blanching close to the optimum conditions provided a protective effect in maintaining cell wall integrity. The results of processing increased firmness in the rehydrated product by a factor of 1.97. Copyright © 2003 Society of Chemical Industry     

Influence of Processing Methodology on Quality of Cucumber Pickles

A study was conducted on the influence of fruit size, blanch temperature, treatment with calcium, and type of acid in cover brine on quality attributes and carbohydrates in nonfermented and fermented cucumber pickles. Firmness was improved by blanching, especially in CaCl₂ solution in both fermented and fresh-pack pickles. Fermentation and acetic acid brine treatments produced the firmest pickles. Size of fruit and length of storage affected quality attributes. The carbohydrate fractions, water-soluble pectin and sodium hexametaphosphate-soluble (SPS) pectin, were correlated with shearpress and sensory firmness. It was concluded that method of processing had a significant effect on quality of pickles.     

Softening of Cucumber Pickles by Cx-Cellulase and Its Inhibition by Calcium

The effects of polygalacturonase free Cx-cellulase alone or in combination with CaCl₂ on softening of cucumber pickles during brine storage were examined. Treating Cx-cellulase preparations with urea eliminated polygalacturonase activity. Pickles exposed to Cx-cellulase remained firm for 4 months. After 4 months, Cx-cellulase mediated softening became apparent. Calcium substantially increased firmness. Cx-cellulase did not reduce the level of firmness attained in pickles exposed to calcium during 12 months of storage.     

Thermal Degradation Kinetics of Agaritine in Model Systems and Agaritine Retention in Canned Mushrooms

The effects of heating and pH on agaritine degradation in buffer, mushroom puree and canned mushrooms were investigated. Ampules containing agaritine with citric-phosphate buffer or agaritine with mushroom puree buffered with the same salts were heated for selected time intervals at temperatures ranging from 101-133°C. Additionally, cans containing quartered mushrooms with brine and buffer were still-retorted using five thermal process schedules with equivalent lethalities for Clostridium botulinum (F_o values). In both the buffer and puree systems, agaritine degradation could be modeled by first-order kinetics. In the canning study mushrooms processed for 68 min at 115°C contained about 23% less agaritine than those processed for 11 min at 127°C.     

Canning Quality Evaluation of Pinto and Navy Beans

Thermal processing of pinto and navy beans at 121.1°C for 16 or 14 min in a still retort gave similar sterilization value (F_o= 10) as the processing at 115.6°C for 45 min. The 121.1°C/16 or 14 min process produced beans with greater firmness than the 115.6°C/45 min process. The addition of CaCl₂ and EDTA improved firmness and color of canned beans. Calcium chloride also reduced clumping and splitting of the canned beans. Sensory evaluation showed that the acceptability of canned beans was reduced when CaCl₂ was increased up to 10 mM. High correlation between firmness and soluble pectin in various bean cultivars implied that soluble pectin content could be used as a parameter for screening bean cultivars with desirable firmness.     

Effect of Fertilization, Postharvest Handling and Blanching Temperature on the Drained Weight of Canned Summer Squash

There was no apparent effect on drained weight or firmness when three rates of calcium fertilization and two rates of potassium fertilization were applied to a test planting from which two harvests of raw summer squash were canned. However, high Ca (L₂) decreased dry matter and increased structural carbohydrates and tissue Ca in the canned product. Precooling increased drained weight and dry matter, but drastically reduced firmness of the canned product. Noncooled canned squash had lower drained weights and pH, but greater firmness and higher water soluble pectin and cellulose content. Blanching at 99°C increased drained weight; blanching at 88°C decreased drained weight, but increased calgonsoluble pectin content.     

Heating Characteristics of Whole Kernel Corn Processed in a Steritort

Cans of whole kernel corn in brine and vacuum-packed corn were heated in an FMC Steritort and in a still retort. Two can sizes for each product were processed to simulate two commercial agitating processing machines. The sterilization values (F_o) and heat penetration factors (j, f_h, f₂) were determined from time-temperature data and were influenced by reel rotational speed, corn fill weight, and brine fill or container headspace. For both products, optimum heat penetration for agitated processing occurred at a ratio of brine-to-corn fill weights of about 35% (normal for vacuum-packed products). Above a threshold value, increasing reel rotational speed did not significantly enhance heating, and with the accompanied reduction in retention time in continuous retorts, F_o values would actually be lowered. Sterilization values were somewhat reduced because of overfills of both corn and brine. For the vacuum-packed product, vacuum level significantly influenced heat penetration only for the still processes.     

Effect of Harvest Date, Irrigation, Maturity and Calcium Addition During Processing on Quality of Canned Summer Squash

Soaking summer squash in calcium prior to commercial blanching at 99°C decreased sloughing, increased sensory firmness and had no effect on lightness or pH of the canned product. Although blanching squash in calcium decreased sloughing, improved lightness, decreased pH and produced off-flavors, the effect of hand blanching at 93°C with no calcium present increased sloughing, lightness, pH, and sensory firmness of the processed product. Adding calcium at the point of squash filling into cans after a commercial blanch produced no change in sloughing, decreased pH, increased sensory firmness and had no effect on lightness. Grade 1 squash exhibited the highest drained weight and lowest sloughing values. Drained weight increased at the end of the harvest season. Method of cultivation had no effect on the quality of canned squash.     

INFLUENCE of BLANCHING TREATMENTS ON the TEXTURE and COLOR of SOME PROCESSED VEGETABLES and FRUITS

Fifteen selected vegetables and fruits were processed by conventional procedures with modified blanching conditions. the texture of blanched and processed samples was determined. Low-Temperature-Long-Time (LTLT) blanching considerably increased the final firmness of sterilized carrot, endive and green bean samples, as well as pasteurized cherry samples. After screening experiments, green bean and endive were chosen for further research. Analysis of variance revealed that LTLT blanching treatments in a blanching solution containing calcium and zinc cation significantly affected the texture and color of processed green bean and endive. the blanching treatments were optimized to improve the texture and color of sterilized green bean and endive.     

Effect of different packing treatments on the microbiological and physicochemical characteristics of untreated green olives of the Conservolea cultivar

Microbiological, physicochemical and organoleptic changes were studied in non‐pasteurised samples of untreated green olives cv Conservolea stored at 20 °C for 180 days under different preservation treatments (acidified brine and modified atmospheres). The microbial flora consisted of lactic acid bacteria and yeasts, while no enterobacteria and pseudomonads were enumerated in any package. Although no thermal treatment was applied to the packages, no sediment formation was observed due to the growth of propionic bacteria. Olives packed in brine supplemented with 0.3% lactic and 0.3% citric acids presented the highest acidity, the lowest brine and flesh pH and the lowest dark brine colour as measured by the parameter A₄₄₀?A₇₀₀. Olives packed in modified atmospheres (vacuum, 40% CO₂/30% O₂/30% N₂ and air) presented a progressive loss of fruit firmness and colour with time. At the end of the storage period, olives packed in aerobic conditions and 40% CO₂/30% O₂/30% N₂ presented the lowest firmness and skin colour and were unacceptable to the panellists. The best quality characteristics were maintained in vacuum‐packed olives, as indicated by the higher organoleptic scores. Firmness degradation followed first‐order kinetics (r² > 0.980) and the expected shelf‐life was 23, 15 and 9 months for olives packed in vacuum, 40% CO₂/30% O₂/30% N₂ and air respectively. Copyright © 2004 Society of Chemical Industry