Juice Color Research Articles

Production and characterization of pineapple-mint juice by spray drying

This work studied pineapple-mint juice drying by spray drying. The effect of 0, 3, and 15% of maltodextrin addition in the solution fed in the spray dryer was evaluated. The results showed that it is possible to dry pineapple-mint juice without a carrier agent. A two-level full factorial design of experiments was applied to quantify the effect of spray drying conditions (including the addition of 3% maltodextrin on pineapple-mint juice) on powder physicochemical properties. The estimated effects demonstrated that all variables have affected responses (except powder solubility). Interested in investigating pineapple-mint drying without maltodextrin, the two-level factorial design was further expanded to a central composite design, and additional experiments were realized, resulting in preservation of the natural green color of pineapple-mint juice, and a yield of 35%. The results suggest that mint may help in pineapple-mint juice drying.

Effects of combination shear stress, moderate electric field (MEF), and nisin on kinetics and mechanisms of inactivation of Escherichia coli K12 and Listeria innocua in fresh apple-kale blend juice

This work explored the possible synergistic effects of simultaneous application of shear stress-moderate electric field (SS+MEF) in combination with nisin (NS) at ambient temperature on microbial inactivation and quality changes of apple-kale blend juice. In microbiological studies, Escherichia coli K12 and Listeria innocua were exposed to a) SS+MEF; b) NS; and c) their combinations either simultaneously (SS+MEF+NS) or sequentially (SS+MEF→NS). Quality parameters, including pH, color, antioxidant capacity, and chlorophyll contents of uninoculated juice were also evaluated. Under individual SS+MEF treatment for 10 min, maximum inactivation levels of E . coli K12 and L . innocua were 5.4 and 5.2 log CFU/mL respectively. NS treatment alone inactivated E coli K12 and L . innocua by 1.0 and 2.6 log CFU/mL, respectively. Nevertheless, subpopulations of live cells observed by flow cytometry and by plate counts were significantly reduced after both simultaneous and sequential combination treatments, in comparison to individual treatments. SS+MEF+NS treatment produced inactivation levels up to 5-log reductions for both microorganism species within 5 min. The modified Gompertz model best-fitted the inactivation kinetics. SS+MEF+NS treatment for 5 min preserved pH, color, antioxidant capacity and chlorophyll contents of the product, suggesting its potential as a non-thermal preservation technique for fruit and vegetable juices. • Simultaneous combination of SS, MEF, and NS inactivates microorganisms. • Synergistic antimicrobial effects were found against E. coli K12 and L. innocua. • Combinations were effective against both Gram-positive and Gram-negative bacteria. • Observed synergisms showed bacterial membrane damage and metabolic change. • Applied combinations did not alter quality attributes of apple-kale blend juice.

Effect of acid adaptation on the resistance of Escherichia coli O157:H7 and Salmonella enterica serovar Typhimurium to X-ray irradiation in apple juice

This study aimed to investigate the effect of acid adaptation on the resistance of Escherichia coli O157:H7 and Salmonella Typhimurium to X-ray irradiation. The non-acid-adapted and acid-adapted E. coli O157:H7 cell counts decreased 8.02 and 5.48 log CFU/mL in apple juice, respectively, whereas the S. Typhimurium cell counts reduced by 3.87 and 3.98 log CFU/mL, respectively, after treatment with 1.0 kGy X-ray. In apple juice, the D5d (dose required for 5-log reduction in cell count) values for non-acid-adapted and acid-adapted E. coli O157:H7 cells were 0.66 and 0.92 kGy, respectively, whereas those for non-acid-adapted and acid-adapted S. Typhimurium cells were 1.40 and 1.30 kGy, respectively. The acid-adapted E. coli O157:H7 cells exhibited higher X-ray resistance than the non-acid-adapted cells in apple juice. However, the acid-adapted and non-acid-adapted S. Typhimurium cells exhibited similar resistance to X-ray irradiation in apple juice. Additionally, the effect of X-ray irradiation on apple juice quality attributes was evaluated. The color, pH, and total phenolic contents of apple juice were not significantly affected (P > 0.05) at all treatment doses of X-ray. The results of this study suggest that the inactivation of acid-adapted cells of E. coli O157:H7, which is the predominant pathogen implicated in apple juice-related disease outbreaks, must be considered for the application of X-ray irradiation in apple juice sterilization process.

Modeling and optimization of sugarcane juice clarification process

Sugarcane juice clarification is an important operation in the production process of sugar industry. At present, the two major production indicators (clear juice color value and gravity purity of the mixed juice) in sugarcane juice clarification process still cannot be measured online, and can only be obtained by offline test. In addition, when production condition changes, the setting and adjustment of the key operational variables are made by experienced workers. The delay caused by the offline test and the randomness of the key operational variables caused by manual adjustment will affect the quality of final product. To address these two issues, we firstly constructed a data-driven model based on the deep kernel extreme learning machine (DK-ELM) to predict the key production indicators for clarification process. The model which combined the kernel method and the multi-layer extreme learning machine (ML-ELM) proved successful in prediction of clear juice color value and gravity purity. Then, we proposed a strategy for optimization of operational variables, avoiding the randomness caused by manual setting. A multi -objective function including the purity and color value was constructed. The niche multi-objective particle swarm optimization (PSO) algorithm was used to solve the multi -objective function under typical working conditions in the production process to get optimal set of key operational variables. The results showed that the niche multi-objective particle swarm optimization (PSO) algorithm can provide optimum production indexes for sugarcane juice clarification.

Immobilization of Laccase on Magnetic Chelator Nanoparticles for Apple Juice Clarification in Magnetically Stabilized Fluidized Bed.

The juice clarification, one of the key steps in juice processing, suffers from haze formation that results from residual phenolic compounds. In this study, laccase was immobilized on metal-chelated magnetic silica nanoparticles and used for continuous juice clarification in a magnetically stabilized fluidized bed (MSFB) assisted by alternating magnetic field. Furthermore, a new combination of laccase catalysis and microfiltration was developed for the juice clarification. Immobilized laccase provided high relative activity within broader ranges of pH and temperature compared to the free enzyme. Magnetic immobilized laccase exhibited the best reaction rate of 12.1 μmol g–1 min–1 for catechol oxidation under the alternating magnetic field of 400 Hz, 60 Gs. No activity loss occurred in immobilized laccase after 20 h continuous operation of juice treatment in MSFB under an alternating magnetic field. Combined with microfiltration after treatment with immobilized laccase, the color of apple juice was decreased by 33.7%, and the light transmittance was enhanced by 20.2%. Furthermore, only 16.3% of phenolic compounds and 15.1% of antioxidant activity was reduced for apple juice after the clarification. By this combination strategy, the apple juice possessed good freeze–thaw and thermal stability.

Effect of oxygen scavenger screw-caps on quality of pineapple juices

Effect of screw-caps with oxygen scavenger bound inside the bore seal of the closure (screw-cap-O2S) was studied on dynamics of ascorbic acid (AA), 5-hydroxymethylfurfural (HMF), antioxidant activity expressed as Trolox equivalent (TEAC) and ascorbic acid equivalent (AAE), total polyphenols content (TPC) and colour changes in pineapple juices stored for 90 days. Results were compared to juices closed with conventionally used screw-caps. Screw-caps with bound oxygen scavenger revealed a stabilization effect on ascorbic acid concentration and colour of pineapple juices. Concentration of ascorbic acid (AA) was significantly lower (p 0.05). Effect of different screw-caps and storage conditions on TPC and AAE values was negligible (p > 0.05). Formation of low molecular weight phenolic fractions and the existence of dynamic processes leading to the formation/elimination of compounds with anti- or pro-oxidant properties are supposed.

Determination and Estimation of the Influence of Different Types of Disturbances on the Thick Juice Colour

Determination and Estimation of the Influence of Different Types of Disturbances on the Thick Juice Colour

Lactobionic acid as a suitable food preservative for yacon juice

Yacon root is known for its antioxidant, prebiotic and insulin modulator benefits. However, like the root, yacon juice exhibits rapid enzymatic browning, requiring treatments such as acidification. Lactobionic acid (LBA) is a promising food ingredient, which contains not only preservative but also nutritional properties. The first goal of this study was to evaluate the influence of combined treatments (blanching, acid pretreatment) and LBA on refrigerated yacon juice (8 °C; 48 h). The analysis of pH, antioxidants, total polyphenols and color, were used to select the optimal combined conditions, which were steam blanching (10 min) + LBA 1%. Secondly, the LBA was compared with citric, malic, tartaric, and ascorbic acids (at 1% levels), where the kinetics of polyphenol oxidases were determined in refrigerated storage of the juice at 8 °C for 48 h. Results showed that LBA, malic and tartaric acids maintained the color of yacon juice and preserved bioactive compounds. LBA and malic acid prevented enzymatic browning with PPO reductions of 80.4% and 79.4%, respectively. This was the first time that LBA has been tested in a refrigerated juice showing significant potential for preservation of color and bioactive compounds in food products.

English

In this study, jambolan and grape juices were used to produce polysaccharide-based edible films by the solvent-casting technique. The polysaccharides used were carboxymethyl cellulose, hydroxypropyl methyl cellulose, high-methoxyl pectin, low-methoxyl pectin, sodium alginate, and locust bean gum. The films exhibited good mechanical resistance and flexibility, with tensile strength (8 to 28 Mpa), elongation at break (6 to 36%), adhesion force (0.4 to 1.4 N), swelling index (1.0 to 2.3), and disintegration time (0.5 to 60 min) that varied as a function of the polysaccharide and the fruit juice used. The surface pH was, respectively, ~5.5 and ~4.6 for the films produced with grape and jambolan juices, regardless of the polysaccharide used. All films presented the typical color of the fruit juices, which was characterized by the L*, a* and b* parameters. The films produced with jambolan juice had the higher anthocyanin content (3.4 mg/g, d.b.) and antioxidant capacity (198 mMol Trolox equivalent/g, d.b.) when compared to those produced with grape juice (0.28 mg/g and 85 mMol Trolox equivalent/g, d.b.). The results are interesting for the food industry, specifically in edible or biodegradable films production, since alternative fruit juices can be used in food formulations and their natural compounds can replace synthetic additives. Key words: Alternatives fruits, Syzygium cumini L., Vitis vinifera L., antioxidant, anthocyanin, natural colorants.

Cooking chicken at home: Common or recommended approaches to judge doneness may not assure sufficient inactivation of pathogens.

About one third of foodborne illness outbreaks in Europe are acquired in the home and eating undercooked poultry is among consumption practices associated with illness. The aim of this study was to investigate whether actual and recommended practices for monitoring chicken doneness are safe. Seventy-five European households from five European countries were interviewed and videoed while cooking chicken in their private kitchens, including young single men, families with infants/in pregnancy and elderly over seventy years. A cross-national web-survey collected cooking practices for chicken from 3969 households. In a laboratory kitchen, chicken breast fillets were injected with cocktails of Salmonella and Campylobacter and cooked to core temperatures between 55 and 70°C. Microbial survival in the core and surface of the meat were determined. In a parallel experiment, core colour, colour of juice and texture were recorded. Finally, a range of cooking thermometers from the consumer market were evaluated. The field study identified nine practical approaches for deciding if the chicken was properly cooked. Among these, checking the colour of the meat was commonly used and perceived as a way of mitigating risks among the consumers. Meanwhile, chicken was perceived as hedonically vulnerable to long cooking time. The quantitative survey revealed that households prevalently check cooking status from the inside colour (49.6%) and/or inside texture (39.2%) of the meat. Young men rely more often on the outside colour of the meat (34.7%) and less often on the juices (16.5%) than the elderly (>65 years old; 25.8% and 24.6%, respectively). The lab study showed that colour change of chicken meat happened below 60°C, corresponding to less than 3 log reduction of Salmonella and Campylobacter. At a core temperature of 70°C, pathogens survived on the fillet surface not in contact with the frying pan. No correlation between meat texture and microbial inactivation was found. A minority of respondents used a food thermometer, and a challenge with cooking thermometers for home use was long response time. In conclusion, the recommendations from the authorities on monitoring doneness of chicken and current consumer practices do not ensure reduction of pathogens to safe levels. For the domestic cook, determining doneness is both a question of avoiding potential harm and achieving a pleasurable meal. It is discussed how lack of an easy “rule-of-thumb” or tools to check safe cooking at consumer level, as well as national differences in contamination levels, food culture and economy make it difficult to develop international recommendations that are both safe and easily implemented.

Effect of Cinnamon Essential Oil Nanoemulsion Combined with Ascorbic Acid on Enzymatic Browning of Cloudy Apple Juice

Enzymatic browning seriously influenced the color and nutrition of fruits and vegetables. This study investigated the effect of cinnamon essential oil nanoemulsion (0.1, 0.2, and 0.4%) combined with 0.05% ascorbic acid (AA) on polyphenol oxidase (PPO) activity and related quality of cloudy apple juice. Cinnamon essential oil nanoemulsion was stable in the presence of AA with different concentrations. The individual cinnamon essential oil nanoemulsion showed 80–90% inhibition of PPO activity, which is not enough to effectively control the browning of apple juice. When the cinnamon essential oil nanoemulsion was combined with 0.05% AA, the cinnamon essential oil nanoemulsion acted as a PPO inhibitor and AA acted as a reducing agent, which completely inhibited PPO activity and preserved the color of apple juice during 48 h of storage at 4 °C. In addition, 0.2% and 0.4% cinnamon essential oil nanoemulsion combined with AA reduced the instability index of apple juice from 0.473 to 0.034 and 0.018, respectively. Furthermore, the combined treatment delayed the degradation of total phenol and AA content in apple juice. Collectively, these results indicated that the combination of cinnamon essential oil nanoemulsion and AA could be used to enhance the inhibition of enzymatic browning and maintain the quality of cloudy apple juice.

Pasteurization of carrot juice by combining UV-C and mild heat: Impact on shelf-life and quality compared to conventional thermal treatment

The combination of UV-C radiation and mild heat (UV-H) treatment is a promising strategy for synergistically increasing microbial inactivation in low UV-transmitting juices. In this research, we explored the suitability of UV-H treatment in carrot juice pasteurization and its impact on juice quality during shelf-life compared to that of thermal pasteurization. UV-H treatment at 60 °C (3.92 J/mL, 3.6 min) enabled reductions of over 5 log10 cycles in the reference pathogens and a significant reduction in spoilage yeasts, bacteria, and bacterial spores. The activity of pectin methylesterase and polyphenol oxidase was reduced by UV-H treatment to levels close to those of low-temperature pasteurization (60 °C/18.1 min). The native population of total aerobic bacteria, lactic acid bacteria, and yeasts and molds of UV-H-treated juice remained undetectable during 29 days of cold storage. Furthermore, viscosity, cloud stability, and the color of fresh juice were better preserved by UV-H treatment than by thermal pasteurization throughout storage.Industrial relevanceThis study demonstrates that UV-H treatment is a beneficial alternative to conventional thermal processing in carrot juice pasteurization, since appropriate inactivation levels of pathogenic and spoilage microorganisms can be reached while better preserving the quality attributes of fresh juice throughout its shelf-life.

Physicochemical properties of grape juice pasteurized by ohmic heating technology

Physicochemical properties are essential factors during processing and preservation of food. The changes in physicochemical properties of the product depend upon the processing technique. The effect of ohmic heating on the some physicochemical properties like pH, TSS, titratable acidity, ascorbic acid, total sugar and colour of grape juice were studied. Grape juice was pasteurized at different combinations of voltage gradient (10-40 V cm-1), temperature (55-85 °C) and holding time (1-5 min). Then the pasteurized juice samples were stored for 21 days at refrigerated condition. The changes in properties were less at low voltage gradient and less holding time. Ascorbic acid was observed to be degraded faster at higher voltage gradients. The pH, TSS and total sugar increased while the titratable acidity, ascorbic acid and colour decreased significantly as the voltage gradient, heating temperature and holding time were increased. Ohmic heating treatment aids in retaining the physicochemical properties for a long time. Based on overall quality of grape juice pasteurized by ohmic heating, the best treatment was 30 V cm-1:85 °C: 5 min.

Effects of Different Preservation Treatments on Nutritional Profile on Juices from Different Sugar Cane Varieties

The commercialisation of sugarcane juice is limited due to its rapid quality degradation. This study was conducted to determine the effect of High Pressure Processing (HPP) and High Pressure Homogenisation (HPH) on physicochemical, antioxidant properties and microbiological quality of red sugarcane juice. The red sugarcane juice samples, Kapur, Madu, Serai and Ragnar were subjected to HPP and HPH at 300 MPa for 2 and 5 min before the analysis was performed. Initial brix content, polyphenol oxidase (PPO) and nutritional content of sugarcane juice values of showed that Madu juice contained the highest total phenolic content (TPC) and antioxidant properties (FRAP and DPPH radical scavenging assay) amongst all variants. HPP-treated juice showed no significant difference to the untreated juice in terms of physicochemical properties (total soluble solid, pH and colour), microbial count and polyphenoloxidase activity. In contrast, HPH showed significant decrease in microbial load and polyphenoloxidase activity. The sugar cane juice subjected to HPP and HPH for 5 min showed significant increase and significant decrease, respectively, in term of TPC as compared to untreated sample. In conclusion, HPP appears to be an effective approach to retain TSS, pH and colour of the red sugarcane juice, while increasing the antioxidant quantity which is desirable in the commercialisation of the juice. However, HPH is a better method to reduce PPO activity and microbial load, thus beneficial in reducing the browning process and potentially extending the shelf life.

Quality Changes in Grape Berry as Affected by the Use of Different Colored Shade Nets Proposed to Alleviate the Adverse Effects of Climate Change

In Turkey, viticulture practices have displayed significant development with the production of high quality fresh grapes, juice, molasses and raisin. Grape berries contain high amount of phenolic compounds collected enormous interest due to their essential function in the improvement of produces attained from grapes, but also for their potential useful health effects as functional food. The purpose of present investigation was to reveal the effects of different colored shade nets on berry skin color and functional properties of grape juice. Four years old vines of ‘Alphonse Lavallée’ table grape were cultivated soilless in about 70 L black plastic pots containing sterile peat and perlite mixture under controlled glasshouse condition. The grapevines were covered with different colored shading nets (yellow, blue, white, red, green and black) at the beginning of the summer period. At commercial maturity, investigations show that berry skin color and the analyzed biochemical features of ‘Alphonse Lavallée’ table grape cultivar displayed great variations in response to the different colored shade net. Such differential effects should be evaluated when the use of shade nets is considered in protected viticulture to cope with environmental constraints. The findings may also be useful for the future experiments under conventional vineyard conditions.

Non-thermal treatment for the stabilisation of liquid food using a tubular cellulose filter from corn stalks

Thermal pasteurisation is used for the microbial stabilisation of foods, but this process compromises quality food properties. This study proposes a novel cold preservation method with filtering materials obtained from agricultural by-products. Nano/micro-porous cellulose materials from native corn stalks (NCS), and the material obtained after delignification, were used as filtering materials for the microbial stabilisation of water and orange juice. The optimisation study of NCS and corn stalk tubular cellulose material (CSTC) to remove yeast Saccharomyces cerevisiae and Lactobacillus casei from water in accordance with processing variables was firstly conducted. Optimisation tests demonstrated the influence of cell concentration, filter size and flow rate on filter removal yields. Then the continuous filtration of commercial orange juice was performed for 20 days to remove S. cerevisiae. The results showed that delignified CSTC was an effective filtering material for removing S. cerevisiae and L. casei from water, and it successfully treated commercial contaminated orange juice. Despite juice colour diminishing when the process started and after filter regeneration cycles with hot water, almost initial parameter values were obtained as the process continued. Therefore, the proposed filtering material is a promising low-cost alternative to existing thermal pasteurisation technologies for liquid foods.

Effect of high-pressure microfluidization on nutritional quality of carrot (Daucus carota L.) juice.

In this study, the effect of high-pressure microfluidization on the colour and nutritional qualities of the orange carrot juice was investigated. The juice was processed at three different pressures (34.47MPa, 68.95MPa and 103.42MPa) with three different passes (1, 2 and 3 passes). After that, total phenolic content (TPC), antioxidant activity, carotenoids, color properties, and total soluble solids content of the processed carrot juice were evaluated. As a result, no specific trends in TPC and antioxidant activity of the juice were observed through the variations of processing conditions. However, microfluidization significantly (p < 0.05) improved the carotenoids content in carrot juice. With increasing number of pass, concentrations of β-carotene and lutein had increased significantly. Similarly, increasing process pressure initially increased carotenoid content significantly (up to 68.95MPa), further increase pressure to 103.42MPa did not cause significant changes in carotenoid concentration. Furthermore, color properties such as lightness, redness, yellowness, and chroma value were reduced significantly with the increase of pressure and the number of passes. The results indicated that high-pressure microfluidization could be used as a novel alternative nonthermal technology to heat pasteurization to improve the color and nutritional qualities in orange carrot juice, resulting in a desirable, high-quality juice for consumers.

Shelf Life and Sensory Evaluation of Hill Lemon (Citrus pseudolimon Tan.) Juice using Organic and Inorganic Preservatives

Hill lemon (Citrus pseudolimonTan.) is a hardy plant and grown well in low and mid hills of Himachal Pradesh. Its juice is preserved and being used as souring agent in many food preparations, pickles and chutneys. The shelf life of Hill lemon juice was assessed by using organic and inorganic preservatives. Boiling of juice till the end of formation of foam/leather and adding organic source of preservative (Salt @ 20gm/L of juice + top dressing of mustard oil @ 20ml/L of juice) was found best and received highest rating on various sensory attributes especially colour and flavour under nine point hedonic scale. This treatment not only enhanced the shelf life of the juice up to 10 months but also retained original flavour and colour of juice. Under inorganic preservatives, Potassium meta bisulphite @0.7 gm/L of juice and Sodium benzoate @ 0.5gm/L of juice, six and five months shelf life was observed respectively. Hence use of organic method for preserving the juice can be a better substitute of inorganic preservatives in many food processing industries.

Effect of dynamic high pressure microfluidization on physical properties of goji juice, mango juice and carrot puree

In this study, the effects of dynamic high pressure homogenization (DHPM) at different pressures and passes on particle size distribution, soluble solids content, pH and color of goji juice, mango juice and carrot puree were studied. The results showed that DHPM reduced the particle size of the samples significantly (p &lt; 0.05). pH and total soluble solids content of samples varied greatly depending on the DHPM treatment parameters. For color analysis, DHPM treatment at higher pressure was beneficial to color improvement, but the number of homogenization passes was not. The results provided a certain reference for the homogenization process in the processing of different fruit and vegetable juice/puree.

Impact of critical high‐intensity pulsed electric field processing parameters on oxidative enzymes and color of broccoli juice

This research evaluated the influence of high-intensity pulsed electric field (HIPEF) processing parameters, electric field strength, treatment time, and polarity on color difference (∆E*), polyphenol oxidase (PPO), and lipoxygenase (LOX) activities in broccoli juice. An optimization of HIPEF processing was accomplished and compared with thermal treatment (90°C/60 s). The lowest RALOX (68.71%) and RAPPO (36.11%) were reached at the strongest HIPEF conditions (35 kV/cm for 2,000 µs in bipolar mode). Bipolar mode pulses showed lower RALOX and RAPPO than monopolar mode. However, polarity did not show a significant effect on ∆E*. LOX was always more resistant to HIPEF treatment than PPO. The optimization process (26.35 kV/cm for 1,235 μs in bipolar mode) showed around 60% of enzyme inactivation and ∆E* = 0.69. Thermally processed broccoli juice exhibited the greatest color difference (∆E* = 7.89). HIPEF processing could be an appropriate technology to preserve the color properties and reduce the enzyme activity of broccoli juice. Practical applications Vegetable juices, in particular broccoli juice is attracting the food industry attention because it contains high amounts of nutrients; however, this fact increase their susceptibility to endogenous enzymes. HIPEF is a nonthermal technology for liquid food preservation that inactivates microorganisms and enzymes without compromising the nutritional and sensorial features of foods. Consequently, this technology could be used in the food industry as an alternative for thermal treatment to inactivate deteriorative enzymes in vegetable juices, offering to consumers a high quality product.