Effect of different pre-treatments and dehydration methods on quality characteristics and storage stability of tomato powder

Dehydration process was carried out for tomato slices of var. Avinash after giving different pre-treatments such as calcium chloride (CaCl₂), potassium metabisulphite (KMS), calcium chloride and potassium metabisulphite (CaCl₂+KMS), and sodium chloride (NaCl). Untreated samples served as control. Solar drier and continuous conveyor (tunnel) drier were used for dehydration. Quality characteristics of tomato slices viz. moisture content, sugar, titratable acidity, lycopene content, dehydration ratio, rehydration ratio and non-enzymatic browning (NEB) as affected by dehydration process were studied. Storage study was also carried out for a period of 6 months for tomato powder packed into different types of packaging materials viz. metalized polyester (MP) film and low density polyethylene. Changes in lycopene content and NEB were estimated during storage at room temperature. Pre-treatment of 5 mm thickness of tomato slices with CaCl₂ in combination with KMS and drying using a tunnel drier with subsequent storage of product in MP bags was selected as the best process.     

Calcium Chelation and Other Pretreatments for Flux Improvement in Ultrafiltration of Cottage Cheese Whey

Cottage cheese whey was treated to minimize effects of calcium on membrane fouling during ultrafiltration in a stirred Amicon cell. The treatments used were stepwise pH adjustment from 4.5 to 1.5; chelation of calcium with EDTA or citric acid; calcium chelation followed by pH adjustment to 2.5; and calcium replacement with sodium by ion exchange. All treatments resulting in elimination of free calcium improved the flux. Highest flux increase (53%) in the 8hr processing runs was for citric acid (I.25 meq/one meq Ca) after pH adjustment to 2.5. Addition of CaC1₂ decreased the flux. Confirmatory experiments with DDS-Lab 20 equipment showed 25% flux increase after treatment with either EDTA (one meq/one meq Ca) or citric acid (I.25 meq/one meq Ca) with pH adjusted to 2.5.     

Effect of Citric Acid on Potato Starch Gelatinization

Coexistent effects of citric acid and acetic acid on gelatinization of potato starch and corn starch are discussed and some difference was found in citric acid but not in acetic acid on potato starch, although any difference was not found between both acids on corn starch. The amylogram of potato starch with EDTA treatment and CaCl₂ treatment supports a presumption that removal of calcium ions bound to phosphate in the starch with citric acid should be responsible to the above acid effect.     

Ash gourd peel wax: Extraction,characterization, and application as an edible coat for fruits

Ash gourd (Benincasa hispida Cogn) is a vegetable used in Asian countries and the peel contains high edible waxy materials. This paper reports extraction, characterization, and utilization of ash gourd peel wax as an edible coating in fruits; with strawberry (Fragaria ananassa) as a model system. Crude wax had melting point of 80°C and molecular weight by number (Mn) and molecular weight by weight (Mw) at 2,277 and 2,323 respectively. Dip method was used to coat crude wax as an emulsion on strawberry. Quantity of wax, concentration of sodium benzoate, and dip time were optimized and the values were 0.5%, 1M, and 3 min, respectively. Results were comparable with carnauba wax coating. Fruits without wax coating spoiled completely in less than 2 days at 25°C. Wax coating enhanced the shelf life to 7 days at 25°C and the properties such as texture, color, weight loss, titrable acidity, and microbial counts were well acceptable.     

Physiological and biochemical changes of different fresh-cut mango cultivars stored at 5 °C

Treatments to inhibit browning, decay and to extend shelf life of ‘Keitt’, ‘Kent’ and ‘Ataulfo’ mango cultivars as a fresh‐cut produce were investigated. Combinations of calcium chloride (CaCl₂), antioxidants [ascorbic acid (AA), citric acid (CA)] and two commercial film coatings resulted in a reduction of browning and deterioration of fresh‐cut mangoes stored at 5 °C, especially for the Ataulfo cultivar. The use of CaCl₂ + AA + CA significantly reduced colour deterioration, loss of firmness and did not affect sensory characteristics of fresh‐cut mango, with a larger effect in the Ataulfo cultivar. In general, these treatments prevented loss of sugar and vitamin C of cubes during storage at 5 °C. Shelf life of this cultivar was 21 days, while that of Keitt and Kent was only 9 and 12 days, respectively. There is a correlation between carotene and vitamin C content of Ataulfo mango and its longer shelf life compared with the other cultivars.     

Gel Properties of Whey Protein Concentrates as Influenced by Ionized Calcium

Ionic calcium in four whey protein concentrates (WPC) was decreased using sodium tripolyphosphate (NaTPP) or ethylenediamine tetraacetic acid (EDTA) and effects on gel properties were determined. Total calcium ranged from 0.22–0.41 g/100g WPC and ionic calcium 2.98–47.25 mg/100g protein. Hardness was maximized and expressible moisture (EM) minimized in three WPC gels with 10 mM NaTPP. EDTA had a similar effect on one WPC gel. Addition of 10 mM NaTPP decreased ionic calcium to 5.23–10.31 mg/100g protein. NaTPP or CaCl₂ did not improve hardness or EM of one WPC gel which contained the lowest total and ionized calcium. Chelating agents were effective in improving gel properties of WPC containing higher than optimal calcium.     

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.     

Effect of pretreatments on quality characteristics and water activity of air-dried litchis (Litchi chinensis Sonn.) cv. Rose Scented

The effect of pretreatments on the quality of dried litchis was studied. Dried whole litchis were brown, blanching in boiling water reduced browning but colour was still disliked. Peeling and destoning fruits before drying gave superior product (extent of browning or EB: 0.27, mean sensory score or MSS: 6.74) and they dried faster. Pre-drying dip of peeled and destoned litchis for 10 min in 2% Na₂SO₃ + 1% sodium metabisulphite at room temperature improved colour (EB 0.03) but reduced MSS (5.80). Litchis syruped in 40% syrup containing 0.5% citric acid and 3000 ppm SO₂ for 30 days gave best dried product (EB: 0.08, MSS: 8.08). They dried faster for first 4h after which untreated peeled and destoned (control) litchis dried faster. Dried syruped litchis were hygroscopic, water activity for product of 11.1% moisture (moisture free basis) was 0.27 and critical moisture content was 20g H₂O per 100g solids.     

Modified Atmosphere and Modified Humidity Packaging of Fresh Mushrooms

Sorbitol and sodium chloride were used to modify the in-package relative humidity (IPRH) of fresh mushrooms (water irrigated and CaCl₂ irrigated) stored in a modified atmosphere package (MAP) at 12°C. No differences were observed for maturity index and microbial population between mushrooms stored in modified atmosphere package (MAP) with or without moisture absorbers. Lower IPRH was observed in packages containing water irrigated (normally grown) mushrooms with sodium chloride, but resulted in over-drying of mushrooms and did not improve color. Normally grown mushrooms with 10 and 15g sorbitol had the best color. IPRH of 87–90%, within 9 days storage was considered optimum. No improvements in quality were found with moisture absorbers with normally grown mushrooms. However, a small amount of sorbitol helped to avoid condensation with CaCl₂ irrigated mushrooms.     

Generation of volatile compounds in Brazilian low-sodium dry fermented sausages containing blends of NaC1, KC1, and CaC12 during processing and storage

Brazilian dry fermented sausages with different salt contents were manufactured: control (2.5% NaCl), 50% salt reduced (1.25% NaCl, F1), 50% replaced by KCl (1.25% NaCl and 1.25% KCl, F2), 50% replaced by CaCl₂ (1.25% NaCl and 1.25% CaCl₂, F3), and 50% replaced by KCl and CaCl₂ (1.25% NaCl, 0.625% KCl and 0.625% CaCl₂, F4). Changes in the composition of volatile compounds were studied during processing (0, 7, and 19 days) and storage (30, 60, and 90 days). Neither reduction nor replacement of NaCl by KCI affected the volatile compounds produced during the manufacturing process, and both increased the volatile compounds from carbohydrate fermentation and amino acid degradation during storage. The addition of CaCl₂ improved the generation of hexanal and (E)-hept-2-enal and other volatiles from lipid oxidation during processing and storage. After 90 days of storage, the control sample showed an increase in the generation of volatile compounds from lipid oxidation.     

Combination treatment of high-pressure and CaCl2 for the reduction of sodium content in chicken meat batters: effects on physicochemical properties and sensory characteristics

A combination of high-pressure processing (HPP, 200 MPa, 10 min) and CaCl₂ (0.2%, w/w) on the cooking loss (CL), expressible moisture (EM), textural properties (hardness, springiness, cohesiveness, chewiness and firmness) and sensory attributes of reduced-sodium (1.25% NaCl) chicken meat batters (RCMB) was investigated. The results revealed that combining HPP with CaCl₂ significantly decreased EM, elevated sensory properties and acted synergistically in reducing CL and improving hardness, chewiness and firmness, which enabled RCMB to obtain quality characteristics similar to those with high salt (2.5% NaCl) content. These changes brought about by combined HPP and CaCl₂ could be attributed to increased apparent viscosity and proportion of immobilised water, enhanced rheological (elastic) properties and a denser, homogeneous protein gel network with evenly dispersed small fat globules. It is interesting to take advantage of the synergy between moderate HPP and low concentrations of CaCl₂ to develop meat products with reduced sodium content.     

Development of Chlorine Dioxide Releasing Film and Its Application in Decontaminating Fresh Produce

A feasibility study was conducted to develop chlorine dioxide (ClO₂)‐releasing packaging films for decontaminating fresh produce. Sodium chlorite and citric acid powder were incorporated into polylactic acid (PLA) polymer. Films made with different amounts of PLA (100 and 300 mg), percentages of reactant (5% to 60%), and ratios of sodium chlorite to citric acid (1:2 or 2:1) were prepared using a solvent casting method. The release of ClO₂ from the resultant films was activated by moisture. Increase of reactants in the films produced more ClO₂ while higher PLA content in the films resulted in less release of ClO₂. The ratio of sodium chlorite to citric acid and activation temperature (22 °C compared with 10 °C) did not affect the ClO₂ release from the films. Antimicrobial efficacy of ClO₂ released from the films was evaluated using grape tomato as a model food. The results indicate that the films were activated by moisture from tomatoes in the package and the released ClO₂ reduced Salmonella spp. and Escherichia coli O157:H7 inoculated on the tomatoes to undetectable levels (<5 colony forming units (CFU)/tomato), achieving more than 3 log reduction. The film‐treated tomatoes did not show significant changes in color and texture as compared to controls during storage at 10 °C for 21 d. This study demonstrated the technical feasibility for development of gaseous ClO₂‐releasing packaging system to enhance microbial safety and extend shelf life of fresh produce.     

On the Degradation of Potato Starch During Acid Modification and Hypochlorite Oxidation

Potato starch (35–40% slurry) was (i) acid modified with hydrochloric acid (0.5-N , 50°C, upto 4.5 h) and (ii) oxidized using sodium hypochlorite (7.5 to 70 mg Cl₂/g starch, 38°C, 2.5 h). Starch degradation over the treatment range was followed by: the number average molecular weight (M _n), alkali fluidity number (AFN), iodine binding capacity (IBC), ash and sodium content of the resultant acid modified starch; and carboxyl content, M _n, AFN, ash and sodium content of oxidized starch.     

Effect of Controlled Atmosphere Storage and Chitosan Coating on Quality of Fresh-Cut Jackfruit Bulbs

Fresh-cut jackfruit bulbs were evaluated for quality changes as effect of an additive pretreatment with CaCl₂, ascorbic acid, citric acid, and sodium benzoate followed by chitosan coating. Different types of samples such as pretreated and coated, only pretreated, only coated, and untreated were subjected to controlled atmosphere (CA) storage (3 kPa O₂?+?6 or 3 kPa CO₂; N2 balance) or normal air at 6 °C. CA conditions, pretreatment, as well as chitosan coating in synergy with each other, could significantly minimize the loss in total phenolics and ascorbic acid content of the samples to the levels of around 5% and 17%, respectively, during extended storage up to 50 days. Chitosan coating could also restrict the changes in microbial load. The CA condition of 3 kPa O₂?+?6 kPa CO₂ was found to render higher efficacy in retaining quality attributes of the samples.     

Effect of Partial Substitution of NaCl with KCl on Halloumi Cheese during Storage: Chemical Composition,Lactic Bacterial Count,and Organic Acids Production

Abstract: The effect of partial substitution of NaCl with KCl on chemical composition, lactic bacterial count, and organic acids profile of Halloumi cheese was investigated. Halloumi cheeses were made and kept in 4 different brine solutions at 18% including NaCl only (HA), 3NaCl : 1KCl (HB), 1NaCl : 1KCl (HC), and 1NaCl : 3KCl (HD) and then stored at 4 °C for 56 d. No significant effect was observed between control and experimental cheeses in terms of moisture, fat, protein, lactic bacterial count, and pH values at the same storage period. There was a significant difference in ash, sodium, and potassium contents among experimental cheeses at the same storage period. Ash, sodium, and potassium contents increased significantly during storage at same salt treatment. There was no significant difference in lactic and citric acid contents among experimental cheeses and that of the control. In contrary, there was a significant difference in acetic acid among experimental cheeses. A strong positive correlation was observed between ash, Na, and K contents. An inverse correlation between organic acids and both Na and K contents was also observed.     

褐变抑制剂对干制香蕉片护色效果的影响

为了提高香蕉片干制后的颜色品质,获得最佳护色方法,以褐变度和L*值为考察指标,研究植酸、抗坏血酸、氯化钠、EDTA、柠檬酸5种褐变抑制剂对干制香蕉片颜色品质影响,并优选出提高干制香蕉片颜色品质的护色方法。结果表明:单一护色剂护色效果依次为植酸柠檬酸EDTA氯化钠抗坏血酸,将鲜切香蕉片放入植酸(质量分数为0.9%)和柠檬酸(质量分数为0.3%)组成的复合护色液中浸泡20 min,干制后的香蕉片L*值达65.93,褐变抑制率达84.4%。     

Effect of 100 kPa O2 pretreatments time on physiology and quality of vacuum packed and coated fresh-cut apples

This research used different 100 kPa O₂ pretreatments time (0, 2, 4, and 6 hr) to investigate their effects on qualities of fresh-cut “Red Fuji” apples during cold storage. Fresh-cut apples were dipped in acid solution (composed of 1.53% ascorbic acid, 1.10% citric acid, and 0.51% CaCl₂) for 15 min and 5 g/L carboxymethylcellulose sodium edible coating (composed of 0.5% CMC, 0.01% Natamycin, and 0.015% Nisin) for 5 min. Then the slices were exposed to 100 kPa O₂ for different time before being vacuumed in polyethylene bags. The results showed that pretreatment with 100 kPa O₂ inhibited the surface browning, polyphenol oxidase and peroxidase activity and malondialdehyde. Moreover, 100 kPa O₂ pretreatment for 4 hr was more effective than other pretreatments time. Intact tissue structure and fewest molds and yeast count during 90 days of storage were also observed in pretreated for 4 hr samples during storage.     

EFFECTIVENESS OF CHLORINE AND NISIN‐EDTA TREATMENTS OF WHOLE MELONS AND FRESH‐CUT PIECES FOR REDUCING NATIVE MICROFLORA AND EXTENDING SHELF‐LIFE1

Efficacy of nisin‐EDTA treatments as a sanitizing treatment for reducing native microflora of whole melons and extending shelf‐life of fresh‐cut pieces was compared to chlorine treatments. Whole cantaloupe and honeydew melons were washed with water, nisin (10 μg/mL)‐EDTA (0.02 M), or 200 ppm chlorine for 5 min at ～ 20C before fresh‐cut preparation and storage at 5C for 15 days with periodic microbiological sampling. In addition, some fresh‐cut pieces were washed with 10 μg/mL nisin‐EDTA or 50 ppm chlorine for 1 min before storage. Changes in appearance, odor, overall acceptability and the shelf‐life of the minimally processed fresh‐cut melons were investigated. Preliminary studies indicated that water washes, EDTA (0.002 to 0.2 M) or nisin (5 to 10 μg/mL) were not effective in reducing the microflora of whole melon when used individually. Nisin‐EDTA and chlorine treatments were significantly (P < 0.05) more effective in reducing native microflora than water washes. Nisin‐EDTA treatments were significantly (P < 0.05) more effective than chlorine in reducing populations of yeast and mold and Pseudomonas spp. on whole melon surfaces but were not as effective as chlorine treatments for reducing aerobic mesophilic bacteria, lactic acid bacteria and total gram‐negative bacteria. Microbial contaminants on fresh‐cut pieces washed with 50 ppm chlorine or nisin‐EDTA were further reduced. However, microbial populations increased throughout refrigerated storage irrespective of treatments. Odor, appearance, and overall acceptability ratings for cantaloupe and honeydew fresh‐cut pieces treated with nisin‐EDTA or chlorine were not significantly (P > 0.05) different from each other throughout the storage period (15 to 21 days). However, both treatments led to significantly (P < 0.05) improved ratings compared to the controls for the fresh‐cut pieces at 9 to 12 days of storage and thereafter. The results of this study suggest that treatments with nisin‐EDTA before and after fresh‐cut processing would improve the quality and extend the shelf‐life of fresh‐cut melon.     

Role of Alpha-Tocopherol, Ascorbic Acid, Citric Acidand EDTA as Oxidants in Model Systems

The effects of four widely employed “antioxidants” on iron-mediated hydroxyl radical formation and lipid peroxidation were studied in aqueous model systems. Iron and copper served as catalysts for the reactions which oxidized ascorbic acid and alpha-tocopherol and reduced oxygen. Ferrous ion spontaneously reduced oxygen to O^?₂ (su-peroxide anion radical) which led to OH (hydroxyl radical) and H₂O₂ generation and lipid peroxidation. Precipitation or sequestration of iron greatly depressed these oxidative events. Complexation by EDTA and citric acid, however, formed catalytically active iron chelates. The concomitant increase in iron solubility explained the substantial enhancement of iron-driven redox reactions by EDTA and citric acid.     

EFFECT OF METHOD OF PRESERVATION OF PULP ON THE QUALITY OF CARBONATED AND NONCARBONATED BEVERAGES PREPARED FROM PEACH FRUIT

ABSTRACT

Peach pulp preserved by different methods, i.e., processing at 100C for 30 min, potassium metabisulphite (KMS; 2,000 ppm), sodium benzoate (750 ppm) and mixture of KMS and sodium benzoate (1,000 and 375 ppm) had no significant effect on total soluble solids (TSS), acidity, TSS : acid ratio, pH of carbonated as well as noncarbonated beverages. Carbonated beverages prepared from pulp with 750 ppm of sodium benzoate retained significantly (P ≤ 0.05) higher carbon dioxide (CO₂) content and CO₂ gas : volume during storage. Color of the beverages prepared from peach pulp containing KMS was better but the beverages prepared from peach pulp preserved by processing and addition of sodium benzoate were organoleptically more acceptable. Both carbonated and noncarbonated drinks remained organoleptically acceptable throughout storage. Suspension of carbonated beverages was significantly (P ≤ 0.05) higher during storage as compared with noncarbonated beverages.

PRACTICAL APPLICATIONS

Peaches are valued as a table fruit for a short period of time from end of April to end of May. The acceptability and utilization of this fruit can be increased by processing it into delicious carbonated and noncarbonated beverages. This will provide nutritious drink to the consumers and also help in increasing the fruit cultivation resulting in good returns to the growers. This study will also help to give a fillip to the establishment of a peach beverage industry world wide.