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1.
Nowadays, the interest in dietary antioxidants, mainly present in fruits and vegetables, has prompted research in the field of commercial polyphenol-rich beverages. The main objective of the present work was to produce new polyphenol-rich beverages using lemon and pomegranate juices in different proportions (at 25%, 50% and 75% for both juices). The bioactive composition (flavonoids and vitamin C) of the mixtures as well as its stability, antioxidant capacity and changes in colour over a 70 days storage period were studied. Our results suggest that the new drink made of 75% of pomegranate juice (PJ) and 25% of lemon juice (v:v), has potential for development of new healthy beverages or food products, emphasised by its high antioxidant capacity determined by its phenolic composition – punicalagin isomers, anthocyanins and vitamin C – and improved colour properties.  相似文献   

2.
Tomatoes are typically not peeled before being made into juice but the peels contain enzymes that affect the odor, flavor, and viscosity of the juice. The peels are removed in the finisher, but their presence during the break process may affect quality. Juice was processed from peeled and unpeeled tomatoes using hot or cold break. The juices were pasteurized by high temperature short time (HTST), low temperature long time (LTLT), or with a retort. The control samples were treated with 10% calcium chloride to stop enzymatic activity in the juice. Sauce was made from juice and the tomato products were analyzed for volatiles, color, viscosity, and by sensory. Cold break juice made with peel contained higher levels of some lipoxygenase‐, carotenoid‐, and amino acid–derived volatiles, than the juice made without peel. Because of the lack of enzyme activity, hot break juices had lower levels of these volatiles and there was no significant difference between hot break juices made with and without peel. CaCl2‐treated and HTST juice had higher levels of most of the volatiles than LTLT, including the lipoxygenase‐derived volatiles. The presence of peel produced a significant decrease in the viscosity of the cold break juice and sauce. There was no significant difference in the hue angle, total soluble solids, pH, titratable acidity, and vitamin C for most of the treatments. The texture, flavor, and overall liking of cold break juice made without peel were preferred over cold break juice made with peel whereas the color was less preferred. Between the sauces no significant differences in preference were obtained.  相似文献   

3.
Our recent work shows that in pomegranate juice the destructive effect of ascorbic acid on anthocyanins is not well correlated with changes in the observed colour. However, the addition of vitamin C to this juice has no additional benefit, since ascorbic acid degradation is very rapid and a slightly orange hue results, after a period of storage, in those juices to which ascorbic acid was added. Data are also included on the influence of storage temperature on juice colour stability, indicating that this parameter is more specific for colour alteration and anthocyanin degradation. © 2001 Society of Chemical Industry  相似文献   

4.
Changes of microbial, physicochemical and sensory properties of mulberry juice processed by high hydrostatic pressure (HHP) (500 MPa/5 min), high-pressure carbon dioxide (HPCD) (15 MPa/55 °C/10 min), and high-temperature short time (HTST) (110 °C/8.6 s) during 28 days of storage at 4 °C and 25 °C were investigated. Total aerobic bacteria (TAB) and yeast and mold (Y&M) were not detected in HHP-treated and HTST-treated mulberry juices for 28 days at 4 °C and 25 °C, but were detected more than 2 log10 CFU/ml in HPCD-treated mulberry juice for 21 days at 4 °C and 14 days at 25 °C, respectively. Total anthocyanins were retained after HHP and reduced by 4 % after HTST while increased by 11 % after HPCD. Total phenols were retained by HHP, while increased by 4 % after HTST and 16 % after HPCD. The antioxidant capacity was retained by HTST and HHP and increased by HPCD. Both total phenols and antioxidant capacity were decreased during the initial 14 days but then increased up to 28 days regardless of storage temperature. The value of polymeric color and browning index decreased and a* increased in HHP-treated and HPCD-treated mulberry juices, while HTST-treated mulberry juice had a reverse result. The viscosity of mulberry juice increased in HHP-treated and HPCD-treated juices, while decreased in HTST-treated juice. During storage, total anthocyanins, total phenols, and antioxidant capacity and color in all mulberry juices decreased more largely at 25 °C than that at 4 °C. Better quality was observed in HHP- and HPCD-treated mulberry juices, and a longer shelf life was observed in HHP-treated samples compared to HPCD-treated ones.  相似文献   

5.
Thirty six commercial European fruit juices were tested to ascertain their antioxidant capacity and polyphenolic composition. Six of the products were labelled 100% pomegranate juice, the others included 20 brands of diluted pomegranate juice or pomegranate blended with other fruit juices and 10 different non-pomegranate fruit juices. The antioxidant capacity of all the juices was determined while anthocyanin, ellagitannin and ellagic acid profiles of the 26 pomegranate juices and pomegranate juice blends were obtained using HPLC-PDA-MS(2). Additional analysis was conducted on seven of the juices using HPLC with an on-line antioxidant detection system. Three of the "pure" pomegranate juices had the highest ellagitannin content and the highest antioxidant capacity. Only one of these three juices was rich in anthocyanins. The other "pure juices" had differences in their HPLC "pomegranate" fingerprint and also had a lower antioxidant capacity, in some cases lower than that of some of the blended juices. Vitamin C rather than phenolic compounds was the major contributor to the antioxidant capacity for some of the juices. Statistical analysis of both the antioxidant assay and the HPLC on-line antioxidant data demonstrated that the ellagitannins were the major antioxidants in the pomegranate juices. The complexity of the polyphenolic profile of pomegranates necessitates the use of HPLC-PDA-MS(2) for a thorough evaluation of juice composition and authenticity.  相似文献   

6.
The objectives of this work were to evaluate infrared (IR) dry blanching in comparison with conventional water blanching prior to hot air drying of mango to inactivate polyphenol oxidase (PPO) and ascorbic acid oxidase (AAO) enzymes, and to study its effect on color change and retention of vitamin C and β‐carotene. Mango cylinders were blanched under similar temperature–time conditions either by IR heating or by immersion in a water bath during 2 min at 90 °C (high‐temperature‐short‐time—HTST) or for 10 min at 65 °C (low‐temperature‐long‐time—LTLT). After blanching mango was hot air dried at 70 °C. PPO was completely inactivated during the blanching treatments, but AAO had a moderate remaining activity after LTLT treatment (~30%) and a low remaining activity after HTST treatment (9% to 15%). A higher retention of vitamin C was observed in mango subjected to IR dry blanching, 88.3 ± 1.0% (HTST) and 69.2 ± 2.9% (LTLT), compared with water blanching, 61.4 ± 5.3% (HTST) and 50.7 ± 9.6% (LTLT). All‐trans‐β‐carotene retention was significantly higher in water blanched dried mango, 93.2 ± 5.2% (LTLT) and 91.4 ± 5.1% (HTST), compared with IR dry blanched, 73.6 ± 3.6% (LTLT) and 76.9 ± 2.9% (HTST). Increased levels of 13‐cis‐β‐carotene isomer were detected only in IR dry blanched mango, and the corresponding dried mango also had a slightly darker color. IR blanching of mango prior to drying can improve the retention of vitamin C, but not the retention of carotenoids, which showed to be more dependent on the temperature than the blanching process. A reduction of drying time was observed in LTLT IR‐blanching mango.  相似文献   

7.
石榴营养酒的酿造工艺研究   总被引:2,自引:0,他引:2  
翟文俊 《食品科技》2006,31(11):205-208
利用成熟石榴榨汁,用100%石榴纯汁,辅以纯槐花蜜调整糖度为原料,加入培育好的酒用酵母菌,在全封闭系统验证下,酿造出石榴营养酒,酒色呈宝石红、晶莹透明、酒香幽雅,具有石榴固有香气。  相似文献   

8.
Thermal and storage stabilities of red radish anthocyanins (RRAs) in various juice beverages (apple, grape, peach, pear, pomegranate and lemon) were studied over temperature range 70–90 °C and 4–25 °C. RRAs degradation in all juice beverages followed first-order reaction kinetics. RRAs showed a much faster degradation rate during storage at room temperature (t 1/2 value ≤84.0 days) than did in refrigerated temperature (t 1/2 ≥value 130.9 days). The rate constant (k), E a and Q 10 values for RRAs in juice beverages varied from 1.33 to 0.33, 47.94 to 14.77 kJ mol?1 and 1.16 to 1.89 at 70–90 °C. During heating, RRAs in peach and pomegranate showed higher stability than others at these temperatures. There was a positive correlation (R 2 > 0.9128) between ascorbic acid content of juice beverages (8–36 mg/100 mg) and stability of RRAs at 70–90 °C. It was found that RRAs in apple and pear juice beverage were more stable than in other juice beverages.  相似文献   

9.
Intact turkey meat was cooked using low temperature long time (LTLT) and high temperature short time (HTST) protocols in a combined ohmic/convection system and compared to conventional (CONV) steam cooking. Both ohmic protocols gave a significantly lighter (p < 0.05) and a more uniform colour vs. CONV, while no significant differences (p ? 0.05) were found in texture profile analysis attributes between LTLT and CONV though HTST showed significantly higher attributes (p < 0.05). Cook loss was significantly (p < 0.05) different between treatments (25.2%, 27.9% and 31.3% for LTLT, CONV and HTST). Sensory studies largely confirmed these observations. Cook values (p < 0.05) were lowest for LTLT (4.0) followed by HTST (5.4) and control (8.5). Lipid oxidation and sulphur-flavour-compound development (measured over 7 days) were higher for conventional than ohmic treatments. Overall, these results demonstrate considerable industrial potential for ohmic heating, yielding high quality products with an 8–15-fold reduction in cooking time.  相似文献   

10.
Ultrafiltration (UF, 0.05 μm) with a ceramic membrane was combined with high-pressure processing (HPP) at 500 MPa/6 min and high-temperature short time (HTST) at 110 °C/8.6 s to process fresh apple juice. The aim of this study was to compare the effect of UF + HPP and UF + HTST on quality features of fresh apple juice and analyze the quality changes of the juice treated by UF + HPP and stored during 60 days at 4 °C. Applying UF, total plate count (TPC) and yeasts and molds (Y&M) significantly decreased by 0.29 and 0.28 log cycle, total phenols and ascorbic acid decreased by 33.50 and 26.52 %, and antioxidant capacity, using the DPPH and FRAP assay, significantly decreased by 26.40 and 25.37 %. Meanwhile, the juice clarity was 99.75?±?0.07 % and seven aroma compounds were changed. TPC and Y&M in juices treated by UF + HPP and UF + HTST were <1 log cycle. When compared to the juice treated by UF + HTST, the juice treated by UF + HPP showed lower browning degree and higher total phenols and clarity, and retained seven main volatile aroma compounds. Fresh apple juice processed by UF + HPP was microbiologically safe (TPC <1.8 log cycles and Y&M <1 log cycle) during 60 days of storage at 4 °C. The first-order model was a suitable model for all quality parameters of refrigerated fresh apple juice; however, rate constant k of first-order model was between ?0.0157 and 0.0350, showing the quality features of the refrigerated juice was stable.  相似文献   

11.
Selected parameters (cooking loss, instrumental colour and texture and sensory quality) of a brine-injected pork muscle cooked by a novel and rapid ohmic cooking protocol were examined and compared with those obtained in conventionally cooked samples. Ohmic samples were cooked using either a low-temperature long-time (LTLT) protocol (2 min equilibration, 5 min ohmic heating to 70 °C, 8 min holding) or a high-temperature short-time (HTST) procedure (2 min equilibration, 6 min ohmic heating to 95 °C) performed within a hot air cabinet set at 80 °C (LTLT) and 100 °C (HTST). Conventional cooking (steam oven at 80 °C for 120 min) was conducted to a core temperature of 70 °C. The LTLT treatment gave a much lower cooking loss value (4–5% lower, p < 0.05) than the other treatments, though the full magnitude of this difference was not completely reflected in the proximate composition of the cooked products. Ohmically cooked ham showed a significantly (p < 0.05) lighter surface colour with Hunter L values of 65.3 (LTLT) and 63.5 (HTST) relative to the control (61.4). Texture profile analysis (TPA) indicated a significant difference (p < 0.05) in hardness (N) especially between the HTST surface (82.1 N) and the conventional centre (58.8 N). Although the ohmic cooking protocols yielded products with quite acceptable eating qualities, sensory evaluation found the overall quality of the conventionally cooked ham to be significantly (p < 0.05) superior, indicating that further optimisation of the ohmic cooking protocols would be required prior to any commercial adoption.  相似文献   

12.
Viscosities of two fruit (lemon and tangerine) juices have been measured with a capillary flow technique. Measurements were made in the temperature range from 303 to 393 K. The range of concentration was between 15 and 40 °Brix for tangerine juice and between 17 and 45 °Brix for the lemon juice. The total uncertainty of viscosity and temperature measurements was estimated to be <0.5% at low concentrations and up to 1.5% at high concentrations and 0.025 K, respectively. The effect of temperature and concentration on viscosity of tangerine and lemon juices was study. The measured values of the viscosity were used to calculate the temperature, (? ln η/?T)x, and concentration, (? ln η/?x)T, coefficients for each juice. The Arrhenius type correlation equations for viscosity were used to represent the temperature dependence of viscosity. The values of the Arrhenius equation parameters (flow activation energy, Ea, and η) were calculated for the measured viscosities of tangerine and lemon juices as a function of concentration. Different theoretical models for the viscosity of fruit juices were stringently tested with new accurate measurements on tangerine and lemon juices. The predictive capability of the various models was studied. The concentration and temperature dependence behavior of the viscosity of tangerine and lemon juices are discussed in light of the various theoretical models for viscosity of fruit juices. The applicability and predictive capability of the models used previously for aqueous solutions to represent the effect of temperature and concentration on viscosity of fruit juices was also studied. New model was developed to represent the combined effect of temperature and concentration on the viscosity of the juices. The average absolute deviation between measured and calculated values from this correlation equation for the viscosity was 0.8% and 2.1% for tangerine and lemon juices, respectively.  相似文献   

13.
Survival of Lactobacillus plantarum in model solutions and fruit juices   总被引:1,自引:0,他引:1  
The aim of the work was to study the survival of Lactobacillus plantarum NCIMB 8826 in model solutions and develop a mathematical model describing its dependence on pH, citric acid and ascorbic acid. A Central Composite Design (CCD) was developed studying each of the three factors at five levels within the following ranges, i.e., pH (3.0-4.2), citric acid (6-40 g/L), and ascorbic acid (100-1000 mg/L). In total, 17 experimental runs were carried out. The initial cell concentration in the model solutions was approximately 1 × 108 CFU/mL; the solutions were stored at 4 °C for 6 weeks. Analysis of variance (ANOVA) of the stepwise regression demonstrated that a second order polynomial model fits well the data. The results demonstrated that high pH and citric acid concentration enhanced cell survival; one the other hand, ascorbic acid did not have an effect. Cell survival during storage was also investigated in various types of juices, including orange, grapefruit, blackcurrant, pineapple, pomegranate, cranberry and lemon juice. The model predicted well the cell survival in orange, blackcurrant and pineapple, however it failed to predict cell survival in grapefruit and pomegranate, indicating the influence of additional factors, besides pH and citric acid, on cell survival. Very good cell survival (less than 0.4 log decrease) was observed after 6 weeks of storage in orange, blackcurrant and pineapple juice, all of which had a pH of about 3.8. Cell survival in cranberry and pomegranate decreased very quickly, whereas in the case of lemon juice, the cell concentration decreased approximately 1.1 logs after 6 weeks of storage, albeit the fact that lemon juice had the lowest pH (pH ~ 2.5) among all the juices tested. Taking into account the results from the compositional analysis of the juices and the model, it was deduced that in certain juices, other compounds seemed to protect the cells during storage; these were likely to be proteins and dietary fibre In contrast, in certain juices, such as pomegranate, cell survival was much lower than expected; this could be due to the presence of antimicrobial compounds, such as phenolic compounds.  相似文献   

14.
To gain more comprehensive knowledge of pomegranate (Punica granatum L.) fruit composition and its impact on juice features, fruits and juices produced from fruits of eleven different provenances were investigated by HPLC–DAD-ESI/MSn for their monomeric phenolic and lignan profiles. Total phenolics and antioxidant capacity were monitored by the Folin-Ciocalteu, ferric reducing antioxidative power and Trolox equivalent antioxidant capacity assays. Peels, mesocarp, seeds and juices obtained from isolated arils (PJAs) as well as from entire fruits were separately analyzed. Ellagitannins were found to be the predominant phenolics in all samples except in PJAs. However, due to the low lignan amounts, only isolariciresinol could be quantitated in peels and mesocarp. The peels and mesocarp revealed highest contents of hydrolyzable tannins (27–172 g/kg and 32–263 g/kg, respectively) and isolariciresinol (4.9–19.8 mg/kg and 5.0–13.6 mg/kg, respectively). To the best of our knowledge, a systematic investigation of monomeric phenolic compounds and isolariciresinol considering diverse pomegranate fruits has been performed for the first time. The study demonstrates that raw material and extraction process have significant impact on juice composition and thus must be carefully selected. Furthermore, pomegranate processors should select juice extraction processes according to the final designation of the product, that is, distinguish between dietary products being rich in phenolic compounds having an astringent taste, and juices for consumption having an appealing taste but lower amounts of phenolics, respectively. This study may further contribute to facilitate authenticity control of diverse pomegranate products and help predict sensory and biofunctional characteristics of pomegranate juices.  相似文献   

15.
Alper N  Acar J 《Die Nahrung》2004,48(3):184-187
Phenolic compounds of fruit juices are responsible for haze and sediment formation as well as for color, bitterness and astringency. The influence of ultrafiltration (UF) and laccase-UF combination was investigated on phenolic contents of pomegranate juices and on filtration output. Laccase-treated and then ultrafiltered pomegranate juices have shown a rapid increase in their color, when compared to only ultrafiltered (control) samples. Kinetic parameters of laccase were also determined. During the oxidation period, the changes occurring in pomegranate juices were estimated from phenolic contents, color and anthocyanin measurements. Results have shown that laccase oxidation produced a significant decrease in phenolic content of pomegranate juices while juice color the increased. However, in recent literatures, the possibility to remove polyphenols in apple juices was reported. We decided in this study that laccase treatment can not be applied due to the loss of natural red color and unwanted dark brownish color formation in pomegranate juice.  相似文献   

16.
Phenolic compounds of fruit juices are responsible for haze and sediment formation as well as for color, bitterness and astringency. The influence of ultrafiltration (UF) and laccase‐UF combination was investigated on phenolic contents of pomegranate juices and on filtration output. Laccase‐treated and then ultrafiltered pomegranate juices have shown a rapid increase in their color, when compared to only ultrafiltered (control) samples. Kinetic parameters of laccase were also determined. During the oxidation period, the changes occurring in pomegranate juices were estimated from phenolic contents, color and anthocyanin measurements. Results have shown that laccase oxidation produced a significant decrease in phenolic content of pomegranate juices while juice color the increased. However, in recent literatures, the possibility to remove polyphenols in apple juices was reported. We decided in this study that laccase treatment can not be applied due to the loss of natural red color and unwanted dark brownish color formation in pomegranate juice.  相似文献   

17.
The thermal inactivation of selected microbes was studied using the low temperature long time (LTLT), high temperature short time (HTST) and 'pot' pasteurization methods. Survivors were enumerated after heating for up to 40 min for the LTLT and HTST pasteurization methods and after heating for up to 30 min for the 'pot' pasteurization method. With the exception of the Bacillus cereus strain, the selected microbes did not survive the LTLT and HTST pasteurization methods. The results from the 'pot' pasteurizer showed that B. cereus, Chryseobacterium meningosepticum, Pseudomonas putida, Acinetobacter baumannii and Escherichia coli strains survived the pasteurization conditions applied, showing that the 'pot' pasteurizer does not pasteurize effectively.  相似文献   

18.
BACKGROUND: Pomegranate is highly valued for its health‐promoting effects. Fruits of nine pomegranate cultivars were analysed for volatile compounds, antioxidant activity and quality parameters, including maturity index and CIEL*a*b* colour. Volatile compounds were isolated from fresh juices using hydrodistillation; extracts were analysed using gas chromatography/mass spectrometry. Fruit colour was influenced by cultivar and grouping of cultivars according to their taste (sweet, sour‐sweet or sour), with sweet fruits having more intense red colour and higher lightness values. RESULTS: A total of 18 compounds were found in pomegranate aroma profiles, including monoterpenes, aldehydes, alcohols, monoterpenoids and linear hydrocarbons. The most abundant compound were trans‐2‐hexenal, 3‐carene, α‐terpinene and α‐terpineol. The total concentration of volatiles ranged from 1.7 to 10.9 g kg?1. Overall consumer liking of pomegranate juices was associated with the presence of monoterpenes such as α‐pinene, β‐pinene, β‐myrcene, limonene and γ‐terpinene. The presence of aldehydes such as hexanol, hexanal and cis‐3‐hexenol was correlated with poor overall consumer liking. CONCLUSION: Fruits from the cultivar Mollar de Elche 2 were those most suited for juice processing because they had the highest total concentration of volatiles, which was related to high overall consumer liking, intense and acceptable fresh pomegranate odour and flavour (high scores of satisfaction degree), medium intensity of red colour and low sourness. Copyright © 2010 Society of Chemical Industry  相似文献   

19.
研究了超高压(HHP,500 MPa/4 min)和高温短时(HTST,95℃/15 s)对甘蔗浊汁和清汁p H、可滴定酸(TA)、可溶性固形物(TSS)、总酚、色泽、褐变度、澄清度、浊度和微生物指标的影响,并分析了4℃,贮藏15 d内甘蔗汁品质的变化。结果表明:HTST和HHP处理对甘蔗汁均具有较好的杀菌效果,HHP和HTST甘蔗清汁p H显著降低,HTST甘蔗清汁可滴定酸(TA)含量升高,HHP和HTST对甘蔗清汁和浊汁的可溶性固形物(TSS)和总酚含量无影响,与HTST相比HHP对甘蔗汁颜色的影响较小,HHP处理后甘蔗清汁澄清度升高,甘蔗浊汁浊度下降,HHP甘蔗汁感官性能优于HTST甘蔗汁。经在4℃贮藏15 d,甘蔗浊汁的菌落总数显著升高,但浊汁和清汁的霉菌和酵母菌数基本保持稳定,贮藏期间甘蔗清汁和HTST甘蔗浊汁p H降低,总酚含量均有明显升高,甘蔗清汁的澄清度和甘蔗浊汁的浊度有所降低,HHP甘蔗清汁的b*值和褐变度增加,HTST甘蔗汁颜色稳定。结论:超高压杀菌有利于保持甘蔗汁品质,是适合甘蔗汁的加工技术。   相似文献   

20.
This paper investigated the feasibility for pasteurizing raw (100 %) pomegranate juice in a commercial scale pulsed electric field (PEF) processing system. The juice was processed at 35 and 38 kV/cm for 281 μs at 55 °C with a flow rate of 100 L/h. Effect of PEF processing on microbial stability, color, °Brix, pH, sediment, antioxidant activity, total phenolic content, anthocyanin, and sensory properties after the treatments and during storage at 4 °C for 12 weeks were studied and compared to those of thermally processed juice. PEF treatments significantly (p?<?0.05) inhibited the growth of total aerobic bacteria, which remained at <2.5 log colony-forming units (CFU)/ml during the 12-week storage. No yeast and mold were detected (<0.69 log CFU/ml) in the PEF-treated juices during storage up to weeks 10 and 12, which is similar to the thermally processed juice. There were no significant differences in pH and °Brix values between the PEF processed juice and unprocessed juice. PEF processing did not alter the contents of total phenolics and anthocyanin as compared to unprocessed juice. PEF processing had significantly (p?<?0.05) less impact on the color of pomegranate juice than thermal processing. PEF-treated juice had the same consumer satisfaction scores as the unprocessed juice, which were significantly (p?<?0.05) higher than thermally processed juice samples. There was no significant difference between the two PEF treatments in all results. This study demonstrated that PEF technology extended microbial shelf-life and preserved the major quality and nutritional characteristics of pomegranate juice, and hence, is technically feasible for commercialization in the juice industry.  相似文献   

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