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.     

Preparation and Partial Characterization of Eggshell Calcium Chloride

To minimize eggshell waste, calcium in eggshells was extracted as calcium chloride using 4% (w/v) HCl solution for an extraction period of 3 hs with the ratio of eggshell to HCl being 1:15 (w/v). After hydrolysis, the residues were removed by centrifugation at 1774 × g for 10 min, and the solution was heated to 110–115°C until dried, this gave an eggshell calcium chloride at a yield of 87.38% (w/w). The calcium chloride powder in this study was composed of 0.3% protein and 94.37% ash, with pH 5.27 and showed high solubility. It contained minute amount of heavy metal constituents within the specification of the Thai Food Act. X-ray diffraction analysis indicated that eggshell calcium chloride powder thus prepared was composed mainly of CaCl₂.2H₂O. The eggshell CaCl₂ was also tested for its functional property as a firming agent in canned rambutan. The results showed that both eggshell and commercial calcium chloride gave a firm texture to canned rambutan, therefore eggshell CaCl₂ can be prepared and used as food processing aids.     

FIRMNESS OF THERMAL PROCESSED ONION AS AFFECTED BY BLANCHING

The pectin methyl esterase enzyme system was shown to be involved in firmness of thermally treated onion in the temperature range 50–70C. Thermal softening of onion at 90 and 100C showed an initial steep negative slope with a shallow negative slope at longer heating time. Low‐temperature blanching at 70C was effective to maintain firm onion tissue exposed to excessive heating. Physical strength of onion was substantially diminished when exposed to a commercial sterilization condition where F₀, extent of thermal sterilization, was 3, and/or more. Blanching in water for 120 min at 70C resulted in a maximum value for the firmness of commercially sterilized onion. Firmness of onion, blanched in calcium brine at a concentration range of 0.0–1.0% (wt) prior to heat treatment, decreased with increasing severity of thermal sterilization treatment. At F₀ = 6, blanching in 0.5% calcium brine resulted in maximum firmness of thermally sterilized onion, approximately 70% of that of raw onion.     

EFFECT OF DIPPING TREATMENTS ON COLOR STABILIZATION AND TEXTURE OF APPLE CUBES FOR INFRARED DRY-BLANCHING PROCESS

This research investigated the effectiveness of dipping treatments on reducing enzymatic browning of apple cubes for infrared dry‐blanching (IDB) process. Apple cubes were dipped in solutions with various combinations of ascorbic acid (AA), citric acid (CA) and calcium chloride (CC) at different concentrations (0.1–1.5%) for up to 10 min. Some dipped samples were further blanched with the IDB method. Color and texture of the dipped samples with and without blanching were determined after the samples were exposed in ambient air for up to 100 min. Results showed that the combination of any two chemicals among the three chemicals tested could effectively reduce browning rate. Dipping treatments of CC or CC + AA resulted in firmer samples after IDB than the controls and those treated with AA + CA. Dipping in 0.5% AA + 0.5% CC for 5 min is recommended as pretreatment of apple cubes for IDB.     

Effects of pretreatments on the texture and ascorbic acid content of frozen plantain pulp (Musa paradisiaca)

The effects of water blanching, steam blanching, microwave blanching and calcium chloride pretreatment on the physical and sensory properties and ascorbic acid content of frozen plantain (Musa paradisiaca L) pulp was studied. After freezing and reheating, the microwave treatment produced a similar texture to that obtained with calcium chloride treatment, and both were significantly (P<0.01) better than conventional water or steam blanching. Microwave treatment improved retention of ascorbic acid.     

Improvements in Canned Lowbush Blueberry Quality

Individually quick frozen lowbush (wild) blueberries (Vaccinium angusrifolium) were canned with 0, 1500, or 3000 ppm calcium from chloride or lactate salts and 0, 0.25, or 0.50% citric acid in water. Physical and pH changes were measured at 0, 6, and 12 mo, and sensory evaluations were made at 3 and 9 mo post-canning. Calcium increased firmness and berry calcium content. Calcium chloride and citric acid reduced pH and increased hue angle and off-flavor; calcium lactate increased drained weight and pH but reduced hue. Response surface methodology predicted changes in calcium lactate-treated berries, but not CaCl₂-treated berries. Optimal conditions were 1200–1800 ppm calcium lactate at 3–6 mo storage.     

EFFECT OF BLANCHING AND SULFITE TREATMENT ON THE QUALITY OF FROZEN CAULIFLOWER

The influence of blanching time and post-blanching sulfite treatment on the sensory quality and texture of frozen cauliflower were assessed after storage at -18°C for up to one year. The treated cauliflower florets, sealed in polyethylene bags, were placed in waxed paperboard cartons and frozen in a contact plate freezer at -35°C. Samples blanched for 3 min and dipped in a solution containing 1000ppm of SO₂ for 5 min gave a significantly (p<0.05) superior product even when stored for one year. The residual SO₂ content of 50 ppm found in these stored samples disappeared after a 3 min cooking in boiling water. Cauliflower texture was influenced by blanching time but the textural differences of blanched samples diminished following freezing and storage. After a 3 min cooking, the texture of all thawed samples were comparable to that of fresh cauliflower cooked for 10–12 min.     

MICROWAVE BLANCHING OF SLICED POTATOES DIPPED IN SALINE SOLUTIONS TO PREVENT ENZYMATIC BROWNING

Response surface methodology was applied to investigate the way in which variables such as time of treatment, sodium or calcium chloride concentrations and lactic acid concentration affect the microwave blanching of potato slices dipped in these solutions. Two three factor-five-level, second order central composite designs were developed to analyze the considered variables. Results showed that, with reference to polyphenoloxidase inactivation, the blanching in calcium chloride-lactic acid solution was more effective than the blanching in sodium chloride-lactic acid solution. Color measurements showed that, in the applied operative conditions, the best results were obtained by short blanching in sodium chloride-lactic acid solution at high lactic acid concentration and low NaCl concentration and by short blanching in calcium chloride-lactic acid at low lactic acid concentration or low calcium chloride concentration.     

Effects of different pre-freezing blanching procedures on the physicochemical properties of Brassica rapa leaves (Turnip Greens, Grelos)

For optimal freeze storage, green vegetables should first be blanched. The present study compared four different procedures for the blanching of grelos (leaves of Brassica rapa L.): steaming for 2 min, immersion in boiling water for 2 min, immersion in boiling water containing 1% citric acid for 1 min, and immersion in boiling water containing 5% citric acid for 1 min. After blanching, the grelos were stored for up to 120 days at ?18 °C, with sampling at two‐weekly intervals for analysis of physicochemical properties (ash weight, vitamin C content, pH, acid value, moisture content and CIE_L*a*b* colour variables). In almost all respects steam blanching gave the best results: notably, vitamin C losses were markedly lower, while moisture content and colour remained closer to those of the fresh product.     

Optimization of Blanching Conditions Prior to Deep Fat Frying of Yam Slices

The effect of low-temperature blanching and frying time at a frying temperature of 170°C on moisture and oil contents, breaking force and colour of yam chips was investigated using response surface methodology to establish the optimum blanching conditions and frying time. A central composite rotatable design was used to study the effects of variation in levels of blanching temperature (60–80°C), blanching time (1–5 min) and frying time (2–6 min) on quality attributes of yam chips. The effect of blanching temperature and frying time was more significant than the time of blanching on the quality attributes. The response variables were fitted to predictive models applying multiple linear regressions. Statistical analysis with response surface regression showed that moisture content, oil content, breaking force and L? (lightness) parameter were significantly (P < 0.05) correlated with blanching temperature and time and frying time. However, the regression equation showed a poor fit for a? and b? respectively. The optimum conditions were a blanching temperature of 70–75°C, blanching time of 4–5 min while frying for about 5 min.     

Optimization of a Diced Tomato Calcification Process

The effect of calcium concentration (0.05-1.45% CaCl₂), temperature of dipping solution (35-65°C), and contact time (0.5-3.5 min) on calcium uptake, firmness and pH of diced tomatoes was evaluated during a calcification process using response surface methods. Temperature had no significant effect on the process. Application of graphical optimization techniques revealed that processing in a solution of relatively low calcium concentration (?0.43% CaCl₂) at ambient temperature (? 35°C) for about 3.5 min would yield a product with Ca⁺⁺ content below the legal limit (<800 μ-g/g), improved firmness (shear force value > 20 N/g), and with pH low enough (<3.95) to eliminate any requirement for acidification treatment.     

Effects of low temperature blanching on texture,microstructure and rehydration capacity of carrots

The effect on quality of stepwise blanching (first 10 min at 65 °C, 50 min holding time, and 1 min at 95 °C) prior to drying of carrot slices was compared with conventional blanching (95 °C, 1 min). As quality parameters, rehydration capacity (effective diffusivity D_e, equilibrium moisture content W_e), texture (puncture test) and microstructure (SEM and Cryo‐SEM) were chosen. Non‐significant differences were found between the W_e of stepwise blanched samples and conventionally blanched ones, both values being similar to the moisture content of fresh carrots. D_e of conventional blanched carrots was higher than for stepwise blanched ones. Maximum force of stepwise blanched samples was higher than those of conventionally blanched ones and not significantly different from fresh carrots. Microstructural observations showed that stepwise blanching preserved cell to cell contacts better than conventional blanching; this fact was attributed to pectin‐methyl‐esterase activation at 65 °C, resulting in the differences in the maximum force between both treatments. Conventionally blanched samples tended to separate along their cell walls, forming voids among the phloem parenchyma cells. These voids would be filled with water during rehydration, thus showing the slightly higher W_e and the higher D_e for conventionally blanched carrots. Copyright © 2005 Society of Chemical Industry     

速冻乌龙头芽加工工艺优化及品质分析

为了优化速冻乌龙头芽加工工艺,通过单因素实验考察了漂烫液pH、漂烫时间、速冻温度对速冻乌龙头芽解冻后色泽（△E值）和汁液流失率的影响,同时采用响应面分析法(Response Surface Methodology,RSM)优化速冻乌龙头芽加工工艺。结果表明:各因素对△E 值和汁液流失率的影响程度由大到小依次均为漂烫液pH>漂烫时间>速冻温度,优化出最佳工艺条件为:漂烫液pH7.50,漂烫时间4.00 min,速冻温度?30.00 ℃,在该条件下得到速冻乌龙头芽的△E 值为22.58,汁液流失率为21.94%,与模型预测值相比相对误差分别为0.58%和1.14%,与预测值相近,且产品品质符合相关标准NY/T1406-2018《绿色食品 速冻蔬菜》的要求。该研究为乌龙头芽速冻加工及开发利用提供一定的理论依据。     

Preparation of Chitosan‐Alginate Nanoparticles for Trans‐cinnamaldehyde Entrapment

Trans‐cinnamaldehyde incorporated chitosan‐alginate nanoparticles were synthesized using the ionic gelation and polyelectrolyte complexation technique. Alginate, chitosan, calcium chloride, and trans‐cinnamaldehyde at predetermined concentrations were complexed electrostatically to optimize particle size and loading efficiency. A final methodology using optimized processing parameters (for example, stirring time, homogenization time, equilibration time, and droplet size) was developed. The best working alginate to chitosan mass ratio was determined to be 1.5:1 at a pH dispersion of 4.7. Particle size (166.26 nm) and encapsulation efficiency (73.24%) were further optimized at this mass ratio using an alginate:calcium chloride mass ratio of 4.8:1, alginate:trans‐cinnamaldehyde mass ratio of 37.5:1, a 18 gauge syringe needle, stirring times of 90 min, 15 min of homogenization at 21000 rpm, and equilibration time of 24 h. Optimized nanoparticles showed increased stability (6 wk) and translucency in solution. The final radical scavenging effect of loaded particles in apple juice was 62% and trans‐cinnamaldehyde was just as available to react in free form as it was in inclusion complexes. The final nanoparticle system with modified and optimized processing parameters reduced the size by 43.6% and increased entrapment efficiency by 17.2%. Nanoparticles resembled a spherical shell and core type arrangement (that is, spherical, distinct, and regular) and were in the size range of 10 to 100 nm.     

Non-enzymatic Depolymerization of Carrot Pectin: Toward a Better Understanding of Carrot Texture During Thermal Processing

ABSTRACT Pretreated carrot discs were thermally processed (90 °C to 110 °C) in closed containers and the resulting textural characteristics were analyzed. The pretreatment conditions used include conventional high‐temperature blanching (90 °C, 4 min), low‐temperature blanching (LTB = 60 °C, 40 min), LTB combined with 0.5% calcium chloride soaking, LTB combined with 2% sodium chloride soaking, high pressure pretreatment (HP = 400 MPa, 60 °C, 15 min), HP combined with 0.5% calcium chloride soaking, and control (non‐pretreated sample). Alcohol insoluble residues (AIR) from the pretreated carrot discs were characterized in terms of degree of methoxylation (DM). The AIR samples were further subjected to fractionation into water‐soluble pectin (WSP), chelator‐soluble pectin (CSP), and sodium carbonate‐soluble pectin (NSP). Heat depolymerization patterns and β‐elimination kinetics were investigated on the different pectin fractions. Thermal texture degradation was strongly influenced by the pretreatment condition used and the processing temperature during subsequent thermal treatment. Pretreatment conditions that showed a significant reduction in DM exhibited decreased WSP content, reduced β‐elimination, and consequently superior textural characteristics. β‐elimination was markedly pronounced in the highly methoxylated WSP fractions. CSP and NSP fractions were insensitive to β‐elimination. A strong correlation (r> 0.95) between thermal texture loss of carrots and β‐elimination kinetics exists. Overall, the benefits of controlled pectinmethylesterase activity in carrot processing were pointed out.     

Modeling of pre-treatment protocols for frozen pineapple slices

Optimization of pretreatments - blanching and additives was carried out for frozen pineapple slices using response surface methodology (RSM). The effect of pre-treatments viz. blanching medium (10-20° Brix sucrose solution), calcium chloride (1000-2000 ppm) and ascorbic acid (200-400 ppm) was studied on hardness (N), colour (L*), syneresis (%) and sensory attributes (colour, aroma, taste, overall acceptability) of the frozen slices after thawing. A Central Composite Rotatable Design (CCRD) was used with six experiments at the central point. The data obtained were analysed employing multiple regression technique to generate suitable mathematical models. Quadratic models were found to fit well (R², 96.72-99.99%) in describing the effect of variables on the responses studied. Optimization of the pretreatments was carried out by maximizing the hardness, L* and sensory responses while keeping the syneresis at minimum level. Compromised optimum values for blanching medium, calcium chloride and ascorbic acid levels were found to be 17° Brix, 1493 ppm and 300 ppm; respectively. The experimental and predicted values showed high correlation coefficients. The optimized pretreatment was found to be helpful in maintaining the quality of frozen pineapple slices in terms of texture, colour and syneresis.     

冷冻保护剂葡聚糖-聚赖氨酸对冷冻皇冠梨品质的影响

为了解冷冻保护剂葡聚糖、聚赖氨酸对冷冻皇冠梨品质的影响,以氯化钙、氯化钙-葡聚糖、氯化钙-聚赖氨酸、氯化钙-葡聚糖-聚赖氨酸为冷冻浸渍液对皇冠梨进行冷冻处理.用无纸化温度记录仪测定冻结时间,分析样品冻结过程中温度随时间的变化,并对冻融后样品进行汁液损失、质构、水分分布等指标测定.结果表明:氯化钙、氯化钙-葡聚糖、氯化钙-聚赖氨酸、氯化钙-葡聚糖-聚赖氨酸浸渍冷冻处理样品通过最大冰晶生成带所需时间分别为12.87、10.12、10.20、7.50 min,加入冷冻保护剂浸渍冷冻的样品解冻后汁液损失显著降低(P<0.05).冷冻保护剂浸渍冷冻处理组抗坏血酸含量、硬度较氯化钙浸渍冷冻对照组均有所提高,样品液泡水(T23)所对应的峰面积S23也有一定程度的提高.研究结果表明,与氯化钙浸渍冷冻相比,加入冷冻保护剂葡聚糖和聚赖氨酸后能有效降低冷冻对梨细胞结构的损害,减少营养物质的流失,有利于维持产品品质.     

Evaluation of blanching requirements of green French bean (Phaseolus vulgaris L.) pods on basis of thermal resistance of its peroxidase

Green pods of French beans CV, pant Anupam were blended with distilled water, filtered and extract pH was adjusted to 5.25, 5.65, 5.85, 6.25 or 6.65 using 20 % citric acid or 1 N NaOH. Thermal inactivation times (TIT) of peroxidase were determined by TIT tube method. The corrected F₁₀₀ [min] and z [°C] at the above five pH values were 1.77 and 15.8, 1.43 and 14.1, 0.95 and 11.0, 0.29 and 8.7, and 0.17 and 8.1, respectively. The corresponding energy of activation values were 157, 177, 218, 286 and 307 KJ mole^?1. The actual blanching times in boiling media calculated from the above data were 4.0, 3.5, 2.5, 1.0 and 0.5 min, respectively, showing that blanching requirements of French beans decreased with increase in the pH of the blanching media.     

Polyphenoloxidase Activity and Color of Blanched and High Hydrostatic Pressure Treated Banana Puree

The effects of blanching and high hydrostatic pressure (HHP) treatments on natural flora evolution, polyphenoloxidase (PPO) activity and color of banana puree adjusted to pH 3.4 and water activity (a_w) of 0.97 were evaluated during 15 days storage at 25°C. Standard plate as well as yeast and mold counts of HHP treated purees were <10 CFU/g throughout storage. Blanching time was found to affect (P<0.05) puree color. HHP treatments retained the initial color of the banana purees. Longer browning induction times and slower browning rates were observed when a longer blanching time was combined with a 689 MPa pressure treatment. A residual PPO activity < 5% was observed in the puree when a 7 min blanch was followed by HHP treatment at 689 MPa for 10 min.     

即食栗蘑加工工艺研究

以新鲜栗蘑为原料,利用单因素和正交试验设计方法,研究硬化、漂烫的最佳工艺及拌料的最佳配方。结果表明:最适的硬化条件是在浓度为0.5%氯化钙和0.5%氯化钠的混合溶液中浸泡40 min。最佳漂烫条件是在浓度为0.3%的柠檬酸和0.06%的抗坏血酸混合溶液中漂烫4 min。最佳拌料配方为每100克栗蘑中加入3 g盐,0.7 g糖,3 g辣椒粉。可制得具有栗蘑特有风味,口感脆嫩,营养丰富,方便安全的新型即食栗蘑食品。