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1.
Litchi fruits (litchis) are highly susceptible to pericarp browning which lowers their commercial value even though the edible portion (aril) remains in excellent condition. Therefore, minimal processing of litchis was carried out. Litchis were peeled, destoned, and arils were treated with antibrowning agents (4.9 g/kg cysteine, 20 g/kg ascorbic acid and 0.134 g/kg 4-hexyl resorcinol) along with osmo-vacuum dehydration (OVD) (502 g/kg sucrose syrup for 10 min at 570 mmHg vacuum followed by a relaxation of 10 min at atmospheric pressure) and stored at 4±2 °C. The samples were analyzed for physicochemical, sensory and microbiological qualities during storage. Changes were found to become significant (P?0.05) after 4 days of storage. During storage for 24 days, a decrease in pH, TSS (°brix), sugars (g/kg), ascorbic acid (g/kg), total phenolics (g/kg), firmness (N), color (L* value) and sensory characteristics was observed whereas an increase in microbial counts (log cfu/g), acidity (g/kg) and drip losses (ml/kg) was observed. The combined treatment of litchis with antibrowning agents and osmo-vacuum dehydration treatment were found to be most effective in preventing the changes and the samples were acceptable (sensory score >7.0) upto 24 days, whereas the samples given only OVD treatment lost acceptability due to poor color after 16 days as compared to 8 days for the control samples (dipped in water for 10 min) during refrigerated storage.  相似文献   

2.
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.  相似文献   

3.
‘B 10’ carambola of ripening stage (RS) 3 and 4 were minimally processed (MP) and then dipped in 0, 15 and 30 mg L?1 ascorbic acid (AA). The 1‐cm‐thick slices were then dried, packed into cling‐wrapped‐foam tray and stored at 7 °C for 0, 3 and 5 days. Skin colour (L*, C* and h°), flesh firmness, soluble solids concentration, vitamin C content, titratable acidity, pH, degree of browning, polyphenoloxidase (PPO) activity and sensory attributes of MP carambola treated with AA were determined. AA treatment had significant effect in decreasing cut surface browning degree but no significant effect on all the selected quality characteristics of the MP carambola. In the sensory evaluation, flesh colour, sweetness, flavour and overall taste were significantly affected by AA treatment especially at 15 mg L?1. The RS of fruit significantly affected skin colour (C* and h°), pH and sensory attributes of colour and flavour of the MP carambola. As storage day (SD) progressed, skin colour (C* and h°), flesh firmness and vitamin C content, cut surface browning, PPO activity and all the sensory attributes of MP carambola decreased significantly. Flesh firmness of the MP carambola was affected by the interaction between AA × SD. Sensory attributes of MP carambola were affected significantly by AA × RS. All the sensory attributes of MP carambola positively correlated to each other but negatively correlated with browning degree. PPO activity positively correlated with browning degree. Copyright © 2007 Society of Chemical Industry  相似文献   

4.
The effect of different modified atmosphere packaging (MAPs) on physical, chemical, microbiological and sensory changes of sea bass fillets when stored at 4 °C and standard light conditions was investigated for up to 21 days and compared to a control batch stored in overwrap. Sea bass fillets were packed using different CO2 and N2 combinations (40% CO2–60% N2; 50% CO2–50% N2; 60% CO2–40% N2), and quality assessment was based on instrumental, chemical, microbiological and sensory analysis. The results showed that MAP extended shelf‐life of sea bass fillets from 7 days (overwrap packaging) to 14 days. Drip loss, pH values and thiobarbituric acid reactive substances (TBARS) measurements were higher in overwrap samples but no differences (P ≤ 0.05) were found between MAP samples. Bacteria grew most quickly and showed higher counts in overwrap samples followed by 40% CO2–60% N2; 50% CO2–50% N2 and finally 60% CO2–40% N2. Sensory analyses were in good relation with chemical and microbiological results establishing best scores and an extended shelf‐life for MAP samples especially in MAPs with high CO2 levels.  相似文献   

5.
The purpose of this study was to investigate the effect of applying two Lactobacillus protective cultures on microbiological, chemical and odour changes during storage of refrigerated vacuum‐packed rainbow trout (Oncorrynchus mykiss) fillets. Lactobacillus sakei CECT 4808 and Lb. curvatus CECT 904T were inoculated individually or in combination into rainbow trout fillets. The samples were vacuum‐packed and stored at 4 ± 0.5 °C and were assessed during a 20‐day storage period for microbiological (Enterobacteriaceae, Pseudomonas spp., lactic acid bacteria (LAB), H2S‐producing bacteria, yeasts and moulds) and chemical (pH, total volatile basic nitrogen, lipid oxidation) parameters and off‐odour. Samples inoculated with Lb. sakei and with both strains had significantly (P≤0.05) lower counts of all microbiological spoilage indicator organisms (Enterobacteriaceae, Pseudomonas spp., H2S‐producing bacteria, yeasts and moulds) than those inoculated with Lb. curvatus or the controls. All chemical parameters examined and off‐odour scores were also significantly (P≤0.05) improved in the samples inoculated with Lb. sakei or with both strains compared with those inoculated with Lb. curvatus or the controls. Lb. sakei generally showed a better preservative effect (P≤0.05) than the combination of strains. Inoculation with Lb. sakei CECT 4808 could provide an additional hurdle to improve shelf‐life of refrigerated vacuum‐packaged trout fillets, as inoculation with this strain resulted in extension of shelf‐life by 5 days. Furthermore, this strain showed some antioxidative ability, which could retard lipid oxidation in fish. Copyright © 2006 Society of Chemical Industry  相似文献   

6.
Edible active coatings (EACs) based on pectin, pullulan, and chitosan incorporated with sodium benzoate and potassium sorbate were employed to improve the quality and shelf life of strawberries. Fruits were washed, disinfected, coated by dipping, packed, and stored at 4 °C for 15 d. Application of EACs reduced (P < 0.05) weight loss and fruit softening and delayed alteration of color (redness) and total soluble solids content. In contrast, pH and titratable acidity were not affected (P > 0.05) throughout storage, and ascorbic acid content was maintained in pectin‐EAC coated strawberries. Microbiological analyses showed that application of EACs reduced (P < 0.05) microbial growth (total aerobic counts, molds, and yeasts) on strawberries. Chitosan‐EAC coated strawberries presented the best results in microbial growth assays. Sensory quality (color, flavor, texture, and acceptance) improved and decay rate decreased (P < 0.05) in pectin‐EAC, pullulan‐EAC, and chitosan‐EAC coated strawberries. In conclusion, EACs based on polysaccharides improved the physicochemical, microbiological, and sensory characteristics, increasing the shelf life of strawberries from 6 (control) to 15 d (coated fruits).  相似文献   

7.
Quality changes and shelf‐life in European sea bass fillets packed under 40% CO2: 60% N2 (MAP) and air (AIR) or prepared from the whole ungutted fish stored in ice (ROUND) were compared. Raw and cooked sensory scores, pH, colour, expressible water, malonaldehyde, total viable count, Pseudomonas spp., H2S‐producing bacteria, Lactobacillus spp., Streptococcus spp., Staphylococcus spp., coliforms and proteolytic counts, were determined until AIR and MAP raw fillet spoilage. Raw ROUND fillets had the best quality and shelf‐life (10 vs. 8 vs. 7 days after slaughtering in ROUND, MAP and AIR, respectively), while the MAP fillets had better sensorial scores, lower pH values and better microbiological counts, but greater lightness values than the corresponding AIR fillets. MAP fillets also had the highest malonaldehyde levels. The higher correlation between Streptococcus spp. and odour scores (r = ?0.971, P < 0.01) compared to the other species could suggest that it is a specific spoilage organism in the MAP condition used.  相似文献   

8.
The effects of extracted natural antioxidant (laurel and myrtle) on the sensory, chemical (TVB‐N, TBARS, PV, FFA and pH) and microbiological (total viable count, psychrotrophic bacteria and Enterbacteriaceae counts) properties of vacuum‐packaged European eel (Anguilla anguilla) stored at 4 ± 1 °C were investigated. The TBARS values of myrtle were significantly lower than that of other groups. The peroxide value was low for European eel treated with myrtle and laurel extract. The FFA‐free fatty acid concentration increased from 0.44 (% oleic acid) (2.03) in the eel during 24 days of storage. The values of pH showed statistically significant (P < 0.05) changes for all groups. The myrtle significantly reduced bacterial growth in fillets (P < 0.05). The microbiological limit of 7 log cfu per gram did not exceed in the treated groups. Data showed that the extracts of myrtle and laurel contain substances that inhibit oxidation of lipids and growth of bacteria in European eel, indicating the potential value of these extracts to extend the shelf life of fish.  相似文献   

9.
Pericarp browning is the main limitation to the postharvest storage, handling and marketing life of litchi fruit. Pre‐storage treatment with pure N2 gas is potentially effective in reducing skin browning and maintaining eating quality of litchis. To better understand inhibition of pericarp browning by a short period of anoxia, adenosine triphosphate (ATP), adenosine diphosphate (ADP) and adenosine monophosphate (AMP) levels, adenylate energy charge and membrane permeability were investigated. Litchi fruit were exposed to pure N2 gas for 6 h and then kept in closed but vented containers for 6 days in the dark at 25 °C and 95–100% relative humidity. Changes in the mentioned fruit physiology and biochemistry parameters and in browning index were measured. ATP concentration and adenylate energy charge decreased rapidly and membrane permeability (relative leakage) increased gradually during storage. Fruit exposed to N2 gas exhibited higher concentrations of ATP, ADP and AMP and adenylate energy charge levels, and lower levels of browning index and membrane permeability, compared to control (non‐N2‐treated) fruit. Greater differences in ATP and ADP concentrations and adenylate energy charge levels of pericarp tissues between N2‐treated and control fruit were more manifest after 4 and 6 days of storage, in association with significant differences at the 5% level in the pericarp browning index. It is suggested that pre‐storage anoxia treatment maintains membrane integrity of pericarp tissues, with high ATP and ADP concentrations and high adenylate energy charge levels. Thus, the loss of cellular compartmentalization (mixing of enzymes and substrates) that leads to enzymatic browning of litchi fruit pericarp is delayed. Copyright © 2007 Society of Chemical Industry  相似文献   

10.
Spices and packaging materials were exposed to γ‐irradiation at a dose of 10 kGy. Luncheon meat was prepared with irradiated or non‐irradiated spices and packaged in irradiated or non‐irradiated packaging materials. Packaged luncheon meat was treated with 2 kGy. Irradiated and non‐irradiated packaged luncheon meat were kept in a refrigerator (1–4 °C) for 12 months. Microbiological, nutritive and chemical characteristics of luncheon were evaluated after processing and during storage; whereas, sensory quality was evaluated only after irradiation. γ‐Irradiation decreased the microbiological counts of spices, packaging materials and packed products and increased its shelf‐life. No significant differences in moisture, protein, fat, pH value, total acidity, lipid peroxide and volatile basic nitrogen were observed as a result of irradiation. Sensory evaluation showed that all the combinations of treated luncheon meats were acceptable. However, the taste, odour, appearance and texture scores of irradiated packaged products were significantly lower than those of non‐irradiated samples.  相似文献   

11.
This study was undertaken with an aim to enhance the enzyme inactivation during high pressure processing (HPP) with pH and total soluble solids (TSS) as additional hurdles. Impact of mango pulp pH (3.5, 4.0, 4.5) and TSS (15, 20, 25 °Brix) variations on the inactivation of pectin methylesterase (PME), polyphenol oxidase (PPO), and peroxidase (POD) enzymes were studied during HPP at 400 to 600 MPa pressure (P), 40 to 70 °C temperature (T), and 6‐ to 20‐min pressure‐hold time (t). The enzyme inactivation (%) was modeled using second order polynomial equations with a good fit that revealed that all the enzymes were significantly affected by HPP. Response surface and contour models predicted the kinetic behavior of mango pulp enzymes adequately as indicated by the small error between predicted and experimental data. The predicted kinetics indicated that for a fixed P and T, higher pulse pressure effect and increased isobaric inactivation rates were possible at lower levels of pH and TSS. In contrast, at a fixed pH or TSS level, an increase in P or T led to enhanced inactivation rates, irrespective of the type of enzyme. PPO and POD were found to have similar barosensitivity, whereas PME was found to be most resistant to HPP. Furthermore, simultaneous variation in pH and TSS levels of mango pulp resulted in higher enzyme inactivation at lower pH and TSS during HPP, where the effect of pH was found to be predominant than TSS within the experimental domain.  相似文献   

12.
The present study deals with the effect of acid whey (AW) on physicochemical properties of non‐nitrite organic dry‐cured pork loins. The loins were divided into three experimental batches: with the curing mixture (C), with sea salt (S) and with sea salt combined with AW (SW). The evolution of physicochemical properties, colour, fatty acid profile and microbiological quality were assessed at 0, 30 and 90 days of refrigerated storage. Physicochemical parameters of dry‐cured organic loins were significantly (P < 0.01) affected by treatment, storage time and the interaction between them. Sea salt in combination with AW was the most successful at reducing the browning reaction involved in the formation of dark colour in dry‐cured loins. Significant reduction in a* value (P < 0.05) caused by replacement of curing salt by sea salt has been less pronounced in sample with AW. Storage diminished (P < 0.01) initial differences in profile of SFA, MUFA and n‐3 induced by treatment method. AW added to uncured loins was able to protect PUFA against oxidation comparable to nitrite. The highest count of lactic acid bacteria (LAB) in dry‐cured loins with AW was accompanied by their lower pH (P < 0.05).  相似文献   

13.
The current trial determined the influence of dietary humate, including humic, fulvic and ulmic acids and some microminerals on the pH, TBARS and microbiological properties of vacuum‐packed and aerobic‐packed breast fillets and drumsticks of broilers. A total of 240 male broiler chicks (Ross‐308) were randomly allocated into four dietary treatments (H0, H1, H2 and H3 groups). A basal diet (H0), basal diet plus 0.1 (H1), 0.2 (H2) and 0.3% (H3) humate (Farmagulator DRY?, Humate, Farmavet International Inc, Kocaeli 41 400, Turkey) were offered during the experimental feeding period. At the end of the trial all chicks were slaughtered. After standard dissection of carcasses, the breasts and drumsticks were divided into two groups for vacuum packaging or aerobic packaging. Packed breasts and drumsticks were stored at 3 °C for 12 days. The breasts and drumsticks were analyzed for pH, TBARS, total mesophilic, total psychrotrophic, lactic acid bacteria and Enterobacteriacea counts at 0, 2, 4, 6, 8, 10 and 12 days of storage. The feeding of humate decreased pH values of breast fillets and drumstick muscles (p < 0.01), especially at the 0.1% level. The TBARS value decreased (p < 0.01) when compared with the without‐humate group (H0). Total aerobic mesophilic (p < 0.01), total aerobic psychrotrophic (p < 0.01) and lactic acid bacteria (p < 0.05) counts were lower in the H3 group than the other groups. The effect of meat type on pH, TBARS, total aerobic mesophilic (p < 0.01) and lactic acid bacteria (p < 0.05) and Enterobacteriacea counts was significant. While the pH and TBARS values of breast fillets were lower than those of drumstick meats, the total mesophilic, total psychrotrophic, lactic acid bacteria and Enterobacteriacea counts of drumstick meats were higher than those of breast fillets. The effect of packaging type on pH (p < 0.01), TBARS (p < 0.01), total aerobic psychrotrophic bacteria (p < 0.01) and Enterobacteriacea counts (p < 0.01) was found statistically significant and the maximum values were determined in the aerobic‐packed samples. In addition, investigated parameters were also affected by storage period. While the total aerobic mesophilic count decreased, the other parameters increased when compared with zero day of storage. Copyright © 2005 Society of Chemical Industry  相似文献   

14.
This study was aimed to investigate the effects of replacing 5% fat and sugar by inulin and lactulose, respectively, on the survival of Bifidobacterium lactis and physicochemical and sensorial characteristics of the ice cream. Total solids, pH, melting rate and sensory scores of low‐fat and/or low‐sugar ice cream samples did not differ significantly from the control. Overrun and hardness of low‐fat samples were significantly higher than that of the control group (P < 0.01). The viable counts of B. lactis in the low‐sugar synbiotic ice creams were significantly lower than that of other groups at the end of 90‐day storage (P < 0.01).  相似文献   

15.
The effect of vacuum impregnation (VI) of fresh‐cut apple wedges with honey, in presence and absence of a browning inhibitor on physicochemical, sensory and antioxidant properties over 7 days of storage at 2–4 °C was studied. Infusion of wedges with honey resulted in very little weight change indicating loss of internal water and ingress of honey carbohydrates into the wedges, hence the correlation coefficients with soluble solids content (r = ?0.91) and dry matter (r = ?0.77). Water infused samples showed the highest water uptake resulting in an increase in weight of 30%. Browning (P < 0.001) and firmness (P < 0.001) of apple wedges were the quality parameters most affected by VI. Samples dipped in browning inhibitor prior AS1 showed slightly better performance than undipped wedges with regard to browning and firmness. Total phenol content and antioxidant activity were significantly (P < 0.001) lower for honey infused apple wedges.  相似文献   

16.
BACKGROUND: Spices are used in different types of foods to improve flavours and are well known for their antioxidant properties. The objective of this study was to determine the effects of rosemary and Hibiscus sabdariffa on the quality attributes of kavurma, a cooked meat product. RESULTS: pH values of samples remained constant (P > 0.05) at about 6.35 during the cooking period, and addition of H. sabdariffa, rosemary or butylated hydroxytoluene (BHT) did not significantly affect pH values (P > 0.05). However, addition of antioxidants decreased (P < 0.05) thiobarbituric acid‐reactive substance (TBARS) values, the highest values being observed in control samples. Lightness (Hunter L) values of control samples increased (P < 0.05) from 28.79 to 37.91 during the first 20 min of cooking. Hunter a and b values were significantly affected (P < 0.05) by process time and addition of antioxidants. Addition of BHT, rosemary or H. sabdariffa did not affect the overall sensory attributes of kavurma during the cooking process. CONCLUSION: Colour values changed during the cooking process, mainly as a result of browning reactions. Addition of rosemary or H. sabdariffa enhanced the colour attributes of kavurma during cooking. Rosemary and H. sabdariffa could be used to modify the quality characteristics and obtain kavurma with a low TBARS value and probably a longer shelf‐life. Copyright © 2009 Society of Chemical Industry  相似文献   

17.
Browning is a serious problem in relation to white wine quality and mostly affects the sensory attributes, whereas its impact on the dietary value of wines has never been investigated. Browning, however, is well known to be associated with polyphenol oxidation, and therefore it may be accompanied by changes in the antioxidant capacity. On the basis of this consideration, experimental white wines vinified and stored under identical conditions were subjected to accelerated browning, and efforts were made to distinguish compositional parameters that might be related to the extent of browning development. Further, the consequences of browning on the reducing power and antiradical activity were assessed. It was shown that none of the parameters examined (titratable acidity, pH, total SO2, total polyphenols and total flavanols) play an important role in browning onset, but SO2 appeared to exert a statistically significant influence (r2=0.6394, P<0.05) on the percentage change in the antiradical activity. Evidence also suggested that browning development might be prominently associated with decreases in both antiradical activity (r2=0.7891, P<0.01) and reducing power (r2=0.6925, P<0.05).  相似文献   

18.
The effect of gamma radiation (0, 1.8, 3.3 and 5.8 kGy) on microbiological, chemical and colour characteristics of vacuum‐packed squid (Illex argentinus) mantle rings was studied. Total viable counts; psychrotrophic bacteria counts, Escherichia Coli, Staphylococcus aureus and Clostridium perfringens; total volatile basic nitrogen (TVBN) and colour difference were analysed during 29 days of storage at 4–5 °C. Higher doses of gamma radiation significantly reduced Total Viable, phychrotrophic counts and TVBN production (P < 0.05) in a dose‐dependent way, delaying squid spoilage. Colour difference of non‐irradiated samples with respect to first day significantly increased while it was constant in radiated samples during 22 days (P < 0.05). Independently from the dose, radiation avoided colour changes of squid rings. Gamma irradiation was effective in delaying deterioration reactions, improving microbiological, chemical and colour quality of vacuum‐packed squid rings stored at 4–5 °C.  相似文献   

19.
This study evaluates effect of tumbling time and cooking temperature on cooking rate, cooking loss (CL), colour, water activity and water‐holding capacity of cooked restructured ham rolls. In experiment were investigated three tumbling times (2, 4 and 6 h) at constant temperature (+4 °C) and three cooking temperatures (76, 86 and 96 °C). It was observed that CL decreased (P < 0.01) from 5.41% to 3.22% with tumbling time (2 h vs. 6 h) but increased (P < 0.01) from 2.35% to 7.25% along with cooking temperature (76 °C vs. 96 °C). In contrast, pH value increased (P < 0.01) from 6.18 to 6.24 with tumbling time (2 h vs. 6 h) but decreased (P < 0.01) from 6.22 to 6.17 along with cooking temperature (76 °C vs. 96 °C). In addition, high temperature had higher efficiency for thermal lethality than low temperature (F0 values were 19 and 92 min at 96 and 76 °C, respectively). Intermediate tumbling (4 h) and cooking (86 °C) could be preferential.  相似文献   

20.
The effects of Fruitone CPA [2‐(3‐chlorophenoxy)propionic acid] (0‐44 ppm) on post‐harvest storage, chemical characteristics and sensory evaluation of pineapples for fresh consumption after storage at 10 ± 1 °C were studied. Pre‐harvest Fruitone treatment beneficially affected the physical characteristics of pineapples, namely increased fruit weight, reduced texture loss, reduced crown size and delayed ripening, but adversely affected their chemical characteristics. Almost all parameters analysed (total soluble solid, titratable acidity, pH and sugars) showed that Fruitone concentrations between 35.2 and 44 ppm were most effective in delaying the ripening of pineapples compared to other concentrations. At these concentrations, Fruitone significantly (P < 0.05) reduced the total soluble solid and pH, but significantly (P < 0.05) increased the titratable acidity. Fruitone treatment was effective in maintaining the TSS and reduced the fluctuation of sugar and the sugar–acid ratio during storage and between fruits. Sensory scores showed that there was a slight increase in the score for odour after 3 weeks of storage between Fruitone‐treated pineapples and control pineapples, while all other sensory attributes (sourness, sweetness, flavour and overall acceptability) were insignificantly different. All sensory attributes correlated positively with pH and sucrose at low concentrations of Fruitone (0–8.8 ppm and 0–26.4 ppm, respectively); with glucose at intermediate Fruitone concentration (17.6–26.4 ppm); with total soluble solid at higher Fruitone concentrations (35.2–44 ppm); and with sugar–acid ratio at all concentrations (except at 44 ppm Fruitone). Copyright © 2006 Society of Chemical Industry  相似文献   

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