Single-strength Juice Research Articles

Non-enzymatic degradation of flavan-3-ols by ascorbic acid- and sugar-derived aldehydes during storage of apple juices and concentrates produced with the innovative spiral filter press

Potentially health-promoting concentrations of flavan-3-ols were previously shown to be retained in apple juices produced with the emerging spiral filter press. Due to the novelty of this technology, the factors governing the stability of flavan-3-ol-rich apple juices have only scarcely been studied. Therefore, we produced flavan-3-ol-rich apple juices and concentrates (16, 40, 70 °Brix) supplemented with ascorbic acid (0.0, 0.2, 1.0 g/L) according to common practice. Flavan-3-ols (DP1-7) and twelve flavan-3-ol reaction products were comprehensively characterized and monitored during storage for 16 weeks at 20 and 37 °C, employing RP-UHPLC- and HILIC-DAD-ESI(−)-QTOF-HR-MS/MS. Flavan-3-ol degradation followed a second-order reaction kinetic, being up to 3.5-times faster in concentrates (70 °Brix) than in single strength juices (16 °Brix). Furthermore, they diminished substantially faster compared to other phenolic compounds. For instance, after 16-weeks at 20 °C, the maximum loss of flavan-3-ols (−70 %) was greater than those of hydroxycinnamic acids (−18 %) and dihydrochalcones (−12 %). We observed that flavan-3-ols formed adducts with sugars and other carbonyls, such as 5-(hydroxymethyl)furfural and the ascorbic acid-derived L-xylosone. Increased degradation rates correlated particularly with increased furan aldehyde levels as found in concentrates stored at elevated temperatures. These insights could be used for optimizing production, distribution, and storage of flavan-3-ol-rich apple juices and other foods and beverages.

Physico-Chemical Characteristics of Crosslinked-Biofilm Made From Passiflora edulis Waste

In numerous tropical countries, Passiflora Edulis which is also known as passion fruit is grown largely for domestic consumption in both the fresh and processed form. Generally, the sweeter purple passion fruit referred to as the granadilla is preferred for consumption as fresh fruit, while the yellow passion fruit is grown mainly to produce juice concentrate or single-strength juice, fruit preserves, and jams, and as a flavoring agent. Passion fruit peel was used to extract pectin to produce biofilm because of its gelling properties and chemical composition to avoid wastage in the juice industry. The objective of this study is to characterize the physical and chemical properties of the pectin-based biofilm. The films were prepared using a casting technique where pectin acts as biopolymer, starch as the base, and glycerol as the plasticizer. Calcium chloride and citric acid were used as cross-linking agents. The results of the solubility test showed that pectin-based biofilms made from passion fruit are more hydrophilic compared to starch, but there was no significant difference in moisture content between the control and film containing 5 and 7 w/v% of crosslinking agent added. The film formed with calcium chloride showed better physical and chemical properties in terms of thickness, solubility, and moisture content. The formulation based on starch and pectin mixture was less rigid and had better elasticity compared to the control film. Therefore, producing films from passion fruit is a new alternative by taking waste from the juice industry.

Evaluation of the Proximate and Antinutritional Properties of Juice and Concentrate Produced from Black Plum (Vitex doniana) Fruit

Black plum (Vitex doniana) juice has received limited attention in terms of comprehensive research on their proximate and anti-nutritional compositions. This study addresses this research gap by exploring the production of dry concentrate, single strength juice and 60% diluted seven juices samples (using different treatments). The investigation of their proximate and anti-nutritional compositions were performed, using standard analytical methods. Also the Juice samples were compared with commercial black currant juice drink. The results of proximate analysis of the dried concentrate revealed a moisture content of 18.85%, ash content of 4.47%, dietary fibre content of 30.14%, fat content of 2.07%, protein content of 8.69%, and carbohydrate content of 35.78%. The single strength juice had moisture content (59.88%), Ash (1.68%), Dietary fibre (11.08%), Fat (0.70%), Protein (2.36%) and Carbohydrate (24.30%). The juices with 60% dilution had moisture content ranging from 81.26% (SSI) to 86.81% (SSC), lower than the commercial juice CEX (90.68%). An increase in the mass of the pectinase enzyme significantly reduced the moisture content, increased the ash content, but increase in the incubation time had no significant difference in the ash content. Preheating (simmering) the fruit before processing did not affect the ash content too. Neither the mass of pectinase enzyme inoculated nor the length of the incubation significantly affected the total dietary fibre of the juice samples. Both increase in the mass of enzyme inoculated and the length of incubation time did not affect the fat content of the juices. The protein content of the juice decreased significantly (p ≤ 0.05) as the mass of the pectinase and the length of incubation and aslo the heating temperature and time increased. The carbohydrate content of the diluted juices was between 8.73% (SSC) and 14.37% (SSI). Statistically, SSC, SSD, SSE, SSF, SSG, and SSI have the same carbohydrate (in quality). SSI had a significantly higher carbohydrate (14.37%). The carbohydrate content of commercial juice (CEX) (9.18%) is much less and significantly lower than that of all processed juice samples. The result of the anti-nutrients showed the concentrate (SSA) and single strength juice (SSB) contain the Oxalate (10.64 and 3.75 mg/100g), followed by Saponin (5.31 and 1.96mg/100g), Tanin (4.82 and 1.95mg/100g), Phytate (3.91 and 1.94mg/100g) while Alkaloid (1.27 and 0.39mg/100g) respectively. The increase in pectinase significantly reduced none of the anti-nutrients. Simmering the fruit before obtaining the pulp used for the juices and increasing the preheating temperature had no significant effect on most of the anti-nutrients except for saponin, which was significantly decreased by the simmering. There were no significant differences (P ≥ 0.05) in the anti-nutrients when the simmering temperature was increased from 43°C to 51°C. Almost no anti-nutrient was in the commercial juice sample (CEX).

Comparative evaluation of apple juice concentrate and spray dried apple powder for nutritional, antioxidant and rheological behaviour

A higher proportion of apples produced in Jammu and Kashmir (J&K) is wasted due to pre-harvest drop which can be utilised for the development of various value-added products. Although apples are mostly processed into single strength juice and concentrate in J&K, there is a need to introduce new apple-based products. Thus, a study was conducted to develop apple powder from apple juice concentrate (AJC) using spray drying technique. AJC was evaluated for physico-chemical composition, phytochemical constituents, flow behaviour, thermophysical aspect, flavour compounds and viscosity, and was compared with spray dried apple powder (SDAP) developed from the same concentrate. Results inferred from the comparison of AJC with SDAP revealed that SDAP recorded lower moisture content (2.91%) and aw (0.217) but significantly (p < 0.05%) higher fibre (0.07%), carbohydrate content (95.28%) and total soluble solids (TSS) (95.78oBrix). An increase in phenolic, anthocyanin and antioxidant potential of SDAP was also recorded. Viscosity analysis demonstrated that AJC possessed content viscous nature with a viscosity of 552.8 mPa-s which was well supported by rheogram depicting Newtonian behaviour of the concentrate. Further, Fourier transform infrared spectroscopy (FTIR) analysis indicated the presence of major ester, aromatic acids, and primary and secondary alcohol groups which were further revealed by GC-MS that detected the presence of major flavour compounds (2-methyl butyl acetate) in AJC. Flow behaviour of SDAP (after reconstitution) depicted non-Newtonian (shear thinning) behaviour with low viscosity. FTIR and GC showed the presence of all chemical constituents already present in AJC thereby confirming efficiency of spray drying process. The results from the comparison study inferred that AJC can prove as an excellent raw material for spray drying after dilution.

Physiochemical and Organoleptic Evaluation of Drink Produced from Pineapple (Ananas comosus) and Tigernut (Cyperus esculentus)

Pineapple, one of the most popular tropical fruits is largely desired for its attractive flavor and can be processed into juice. Fruit juice blends can be produced from various fruits or food materials such as tigernut an underutilized tuber, in order to give better quality drink nutritionally and organoleptically. This work therefore evaluated some quality attributes of the beverage produced from tigernut and pineapple. Tigernut and Pineapple fruit were purchased from local market at Ogbomoso. Single strength juice was produced from pineapple fruit while the tigernut milky extract was produced. The pineapple juice was blended with tigernut milky extract in different proportions (95:5, 90:10, 85:15, 80:20 and 75:25%) while 100% pineapple juice served as the control and were analyzed for physiochemical composition and sensory evaluation (Colour, flavor, taste and overall acceptability). The data obtained were subjected to statistical analysis. The results showed that the physiochemical properties of juice compared relatively well with the control and sensory evaluation showed that all the juice samples were well acceptable in terms of colour, flavour, taste and overall acceptability. The juice blend could be recommended to every household for its nutritional and therapeutic properties.

Treatment with high hydrostatic pressure and supercritical carbon dioxide to control Alicyclobacillus acidoterrestris spores in apple juice

Alicyclobacillus acidoterrestris is a thermoacidophilic and spore-forming bacterium that can develop in pasteurized juices. However, there are innovative technologies for food processing and preservation such as high hydrostatic pressure (HHP) and supercritical carbon dioxide (SCCD) that can be used to inactivate these bacteria.The objective of this study was to investigate the effect of SCCD and HHP on inactivation and germination of spores of two A. acidoterrestris strains.Spores were suspended in apple juice (70.7, 35.5, 23.7, 11.2 °Bx) and treated with SCCD: 60 MPa/50–75 °C/20–40 min and HHP: 300 MPa/50–75 °C/5–15 min. The number of surviving population was determined by the plate method on BAT-agar with or without heat treatment (80 °C, 10 min).After 40 min of SCCD treatment at 60 MPa, 75 °C, germination of A. acidoterrestris TO-169/06 spores in apple juice (11.2 °Bx) was 3.9 log of which 3.4 log were inactivated. Under the same process conditions but in the 70.7 °Bx juice much lower degree of germination (0.9 log) and inactivation (0.5 log) was obtained.In the case of A. acidoterrestris TO-169/06 strain HHP processing at 300 MPa, 50 °C, 15 min in apple juice (11.2 °Bx) 4.4 log of spores germinated of which 3.7 log were inactivated.In the contrary, under the same conditions, in apple juice concentrate germination and inactivation of the spores was 1.5 log and 0.9 log resp. The spores of the A. acidoterrestris TO-117/02 strain were significantly more resistant to SCCD and HHP on the used parameters.These results demonstrate that SCCD and HHP combined with moderately elevated temperature may be a useful technique for inactivation of A. acidoterrestris spores in single strength juices.

Pomegranate Processing and Value Addition: Review

Minimally processed ready-to-eat pomegranate arils have become popular due to their convenience, high value, unique sensory characteristics, and health benefits. Pomegranate is one of the most important fruit crops in India because of its adaptable nature, high profitability and being cultivated on a commercial scale in India and the fruits are good source of nutrients and bioactive compounds, mainly anthocyanins which exhibit strong chemo-preventive activities such as anti-mutagenicity, anti-hypertension, anti-oxidative potential and reduction of liver injury. The research on the development of the new pomegranate derived products such as minimally processed pomegranate seeds, jams, marmalades, single strength juices, jellies, juice concentrates, frozen seeds, refrigerated seeds, seeds in syrup, candied arils, arils in brandy and in vinegar, carbonated beverages, pomegranate wine, pomegranate syrup etc. has been carried out. The processed products such as anardana, juice, concentrate; syrup and jelly were highly acceptable because of their nutritive and dessert qualities and palatability. The modified atmosphere packaging offered an additional innovative tool for the optimal use and value addition of lower grade pomegranate fruits. The minimally processed pomegranate arils and frozen arils packed in punnets and pomegranate juice are the most appealing products to consumers than whole fruit. Pomegranate juice can be used in beverages, for jellies, for preparation of pomegranate juice concentrate, as flavouring and colouring agents and for dietetic and prophylactic treatment purposes. This new sector of pomegranate industrial processing will allow the use of non commercial pomegranate fruits with some physical defects and fruit disorders, having the good quality juice and seeds, to the preparation of these new products, thus improving pomegranate utilization for human health.

Quantification of patulin in fruit leathers by ultra-high-performance liquid chromatography-photodiode array (UPLC-PDA)

Patulin is a mycotoxin commonly found in certain fruit and fruit products. For this reason many countries have established regulatory limits pertaining to, in particular, apple juice and apple products. Fruit leathers are produced by dehydrating fruit puree, leaving a sweet product that has a leathery texture. A recent report in the literature described the detection of patulin at substantial levels in fruit leathers. To investigate this further, an ultra-high-performance liquid chromatography-photodiode array (UPLC-PDA) method was developed for the sensitive detection of patulin in fruit leathers. Investigations were also made of the suitability of direct analysis in real time-mass spectrometry (DART-MS) for detection of patulin from the surface of fruit leathers. Results indicated DART-MS was insufficiently sensitive for quantification from the surface of home-style apple leathers, although patulin spiked onto the surface of leather or peel could be detected. The UPLC-PDA method was used to determine the fate of patulin during the preparation of home-made fruit leathers. Interestingly, when a home-style process was used, the patulin was not destroyed, but rather increased in concentration as the puree was dehydrated. The UPLC-PDA method was also used to screen for patulin in commercial fruit leathers. Of the 36 products tested, 14 were above the limit of detection (3.5 μg kg–1) and nine were above the limit of quantification (12 μg kg–1). Positive samples were confirmed by UPLC-MS/MS. Only one sample was found above the US regulatory limit for single-strength apple juice products (50 μg kg–1). These results suggest patulin can be concentrated during preparation and can be found in fruit leathers. The limited survey suggests that patulin is fairly prevalent in such commercial products, but that the levels are usually low.

Effect of removal of browning substrates on sensory quality of orange juice and semi-concentrates during storage

Effect of removal of reaction substrate (amino acids) from sweet orange juice by using cation exchange resin (CER) was studied for browning reduction and retention of sensory quality characteristics of single strength juice and semiconcentrates of 15 and 30° Brix during storage. Single strength juice alongwith semi-concentrates of 15 and 30°Brix were stored for a period of one month at three storage conditions viz., refrigerated condition (6±2°C, 92% RH), ambient condition (room temperature i.e. 20±4°C, 73% RH) and accelerated temperature (37±2°C, 65% RH). The concentrates prepared from cation exchange resin treated juice exhibited higher sensory scores w.r.t. colour, flavor and overall acceptability. Overall acceptability of the product ranged between 8.08 and 7.27 on 9 point hedonic scale, at various intervals upto 30 days of storage. Significantly higher score was obtained by the products prepared from CER treated juice (8.03) as compared to that of those prepared from untreated juice (7.33). Concentrates stored at lower temperatures experiences lesser changes and thus better sensory scores at all storage intervals.

Effect of Cation Exchange Resin Treatment on Reduction of Non-Enzymatic Browning of Orange Juice and Semi-concentrates during Storage

Effect of removal of reaction substrate (amino acids) from sweet orange juice by using cation exchange resin was studied for reduction of browning of single strength juice and semi-concentrates of 15 and 30°Brix. Cation exchange resin (CER), Dowex-50W was used for removal of amino acids. The treated and untreated juices were concentrated to 15 and 30°Brix in a rotary vacuum evaporator. Single strength juice alongwith semi-concentrates of 15 and 30°Brix were stored for a period of one month at refrigerated, ambient and accelerated temperature (37±2°C, 65% RH). During 30 days storage, loss of amino acids was mere 3.07% in the concentrates prepared from cation exchange resin treated juice as compared to about 6.68% loss in the products prepared from untreated juice. Ascorbic acid content showed a net loss of 14.59% (dwb) after 30 days storage in products prepared from untreated juice as compared to far lesser losses of just 4.85% (dwb) in the products prepared from cation exchange resin treated juice under similar conditions of storage. Total sugar registered a net loss of 3.52% on dry weight basis. Treated juice showed higher amount of total sugars with mean value of 75.48% as compared to untreated juices with corresponding value of 71.01%. Cation exchange resin treatment of malta juice resulted into about three folds in non-enzymatic browning during storage.

Reduction of non-enzymatic browning of orange juice and semi-concentrates by removal of reaction substrate.

A study was conducted to standardize the technology for the removal of amino acids (one of the browning reaction substrates) from sweet orange cv. Malta Common juice to reduce colour and quality deterioration in single strength juice and during subsequent concentration. Juice of sweet orange (Citrus sinensis) cv. Malta Common fruits was extracted by screw type juice extractor, preserved in 500ppm SO2 and clarified by using "Pectinase CCM" enzyme (0.2% for 2h at 50 ± 2°C). For removal of amino acids juice was passed under gravity through a glass column packed with an acidic cation exchange resin (CER), Dowex-50W and quantity to be treated in one lot was standardized. The CER treated and untreated juices were concentrated to 15 and 30°Brix in a rotary vacuum evaporator. Results indicate that 121ml of orange juice when passed through a glass column (5cm internal diameter) packed with cation exchange resin (Dowex-50W) upto a height of 8cm, could remove about 98.4% of the amino acids with minimum losses in other juice constituents. With cation exchange resin treatment, the non-enzymatic browning and colour deterioration of orange juice semi-concentrates was reduced to about 3 folds in comparison to untreated counterparts. The retention of vitamin C and sugars was also better in semi-concentrates prepared from cation exchange resin treated juice. Thus, cation exchange resin treatment of orange juice prior to concentration and storage is highly beneficial in reduction of non-enzymatic browning, colour deterioration and retention of nutritional, sensory quality of product during preparation and storage.

Full scale plant with membrane based concentration of blackcurrant juice on the basis of laboratory and pilot scale tests

A conceptual process design with the use of integrated membrane processes is prepared for blackcurrant juice concentrate (BCJC) production to replace traditional multiple step evaporators and aroma recovery. The combination of membrane processes includes aroma recovery with vacuum membrane distillation and water removal by reverse osmosis, nanofiltration and direct contact membrane distillation. It has been combined with optimization of membrane performance and juice quality in mind. The annual production scale is 17,283ton of 66°Brix out of single strength juice. The operation cost is 0.40€/kg BCJC, which is lower than the price of a traditional operation by about 43%. Therefore, the economical potential of the process is very promising and could supersede conventional evaporators.

Stable isotopes determination in some Romanian fruit juices

The characterisation of 45 Romanian single-strength fruit juices (apples, pears, plums and grapes) collected from different Transylvanian areas by means of stable isotope approach are presented and discussed in this study. We measured 2H/1H, 18O/16O ratios from water juice and 13C/12C from pulp and compared these results with those already reported in the literature for single-strength juices, in order to see how the geographical and climatic conditions of Transylvania and the meteorological peculiarities of the year 2010 influence the isotopic composition of the investigated fruit juices. The δ13C mean values that we found for apple pulp picked up from different Transylvanian areas show slight differences, probably due to the environmental conditions of the plants. No significant correlation either between the variety of apple or the geographical origin and δ13C value was established.

CLARIFICATION AND GELATION OF A MINIMALLY HEATED ORANGE JUICE CONCENTRATE DURING ITS REFRIGERATED STORAGE

ABSTRACT The refrigerated storage of orange concentrates low in pulp content could be an interesting procedure of preservation of concentrates not submitted to high temperature treatments. Orange concentrate of 42°Brix with low pulp content, treated at a very low temperature (60C for 15 s) to avoid microbial spoilage, was stored for 6 months at 3C. The losses of cloudiness during the storage were higher than that of the single strength juice also treated at 60C for 15 s. Gelation of concentrate was detected initially, being the storage modulus higher than the loss modulus at the end of the first month of storage. In any case, the degree of gelation observed after 6 months was far from the substandard quality, according to Florida Statutes. The clarification of this orange concentrate is the factor limiting of its shelf life. Consequently, experiences using heat treatments slightly higher must be planned to delay the loss of cloudiness. PRACTICAL APPLICATIONSCitrus juice industries use to store concentrates of different characteristics (color, °Brix/acid ratio) that are later blended in proper proportions to obtain final products with uniform characteristics. Refrigerated concentrates are easily handled but pectin methylesterase (PME) activity can damage them and, thus, frozen storage is preferred.As PME is associated with cell walls, its activity should be reduced by removing part of the pulp. This paper analyzes the effect of the residual PME activity on colloidal stability of low pulp content concentrates measured by the losses of turbidity and the changes in rheological properties.

Prevention of the accumulation of Alicyclobacillus in apple concentrate by restricting the continuous process running time

To study the accumulation of vegetative cells and endospores of Alicyclobacillus, as well as viable aerobic counts during the continuous production of apple juice concentrate. Apples were processed for a continuous process running time of 108 h (processing rate 1·8-2·0 t h(-1) ) without clean-in-place (CIP) procedures in-between different batches. Samples from single-strength apple juice, concentrate after evaporation (± 30°Brix), the final product (concentrate pasteurized at 102-104°C for 90 s) and condensate water (by-product of the juice concentration process) were collected every 12 h. From 12 to 84 h of processing, vegetative Alicyclobacillus counts in single-strength apple juice increased significantly (P < 0·05) from 1 to 3·15 log(10) CFU ml(-1). Accumulation patterns of vegetative cells in apple concentrate and the final product were similar from 24 to 84 h of processing, with the respective counts increasing from 0·13 to 1·63 and 0·01 to 1·69 log(10) CFU ml(-1). The highest Alicyclobacillus endospore counts in single-strength juice, concentrate and the final product was at 84 h of processing with 1·32, 1·59 and 1·64 log(10) CFU ml(-1), respectively. Alicyclobacillus vegetative cells and endospores accumulate in fruit concentrates during a continuous process running time of 108 h. In conjunction with good manufacturing practices, fruit concentrate manufactures can minimize Alicyclobacillus accumulation in fruit concentrates by limiting the continuous process running time between clean-ups to under 84 h.

Effects of Concentration Prior to Cold-Stabilization on Anthocyanin Stability in Concord Grape Juice

The color of Concord grape juice produced by concentration before cold-stabilization and detartration (direct-to-concentrate, DTC) was compared to juice produced via cold-stabilization prior to concentration (standard concentrate, SC) and evaluated by several metrics. Using the Boulton copigmentation assay, the majority of the absorbance at 520 nm in bottled SC juice (72%) was due to monomeric anthocyanins. Following reconstitution, DTC juice had a 63% greater absorbance at 520 nm than SC juice. A significant loss of anthocyanins was observed using a paired t test during cold-stabilization of single-strength juice during SC processing (mean loss: 79 mg/L as cyanidin-3-glucoside, 23% of total anthocyanins), while no significant loss of anthocyanins or change in other color metrics was observed during cold-stabilization of DTC concentrate. The concentration of anthocyanins in the SC bitartrate crystals was 0.80% w/w compared to 0.13% w/w in the DTC bitartrate crystals. Between DTC and SC, no difference in copigmentation was observed in cold-stabilized concentrate or reconstituted juice, indicating that the increased stability of anthocyanins could not be credited to greater copigmentation in DTC during detartration. HPLC analyses indicated that anthocyanin species with higher pKh and thus proportionally greater flavylium ion concentration at juice pH are preferentially lost during SC processing. The proportional changes in color metrics during shelf life stability testing (0-16 weeks, 2-30 °C) were not significantly different between SC and DTC juices.

The combination of stable isotope abundance ratios of H, C, N and S with 87Sr/86Sr for geographical origin assignment of orange juices

Abstract Within the EU-project “Pure Juice” established stable isotope methods (δ2H, δ13C, δ15N) have been applied and improved in order to determine and verify the geographical origin of orange juices. In addition, new approaches employing analyses of δ34S and 87Sr/86Sr have been developed and tested. Approximately 150 authentic orange juice samples from several regions in North- and South-America, Africa and Europe have been analysed. A discrimination of orange producing regions, based on the results which ultimately depend on geographical, climatic and lithological differences was successfully performed. Furthermore, we demonstrate that blending of single strength juice by adding concentrate can be revealed by comparing 87Sr/86Sr of soluble and insoluble components of the juices. We conclude that regional assignment of orange juice samples is most successful when single parameters are combined in a “multi-element approach”.

Orange ( Citrus sinensis) juice concentration by reverse osmosis

Single strength orange juice was concentrated by reverse osmosis in a plate and frame pilot plant with 0.72 m 2 of filtration area. Three transmembrane pressures, 20, 40 and 60 bar, were evaluated and concentration factors of 2.3, 3.8 and 5.8 were obtained. At these transmembrane pressures the final soluble solids contents were of 16, 28 and 36 °Brix, respectively. The vitamin C content increased from 29.3 mg ascorbic acid/100 g (single strength juice) to 53.9, 82.7 and 101.1 mg/100 g, in the concentrated juices obtained at 20, 40 and 60 bar, respectively. Simulating the continuous process, the permeate flux was 28 L/h m 2 when the transmembrane pressure was 60 bar, while the processes carried out at 40 and 20 bar, presented, respectively, 20 and 11 L/h m 2. The sensory evaluation of the reconstituted juice obtained by dilution of the concentrated juice showed that this product had lost its characteristic aroma and flavour when compared to the fresh orange juice. In a second experiment, some sensory attributes were evaluated in the reconstituted juice obtained by two concentration processes: reverse osmosis and thermal evaporation. The juice from reverse osmosis process had a best preserved flavour. It was concluded that it is feasible to concentrate orange juice by reverse osmosis, maintaining its sensory and nutritional characteristics.

Anthocyanin Pigment Composition of Blackberries

ABSTRACT: The anthocyanin pigments in 51 blackberry samples were isolated and characterized by highperformance liquid chromatography (HPLC) with UV-visible detection, electrospray mass spectroscopy (ESMS), and hydrolysis and saponification reactions. Five pigments were detected: cyanidin-3-glucoside, cyanidin-3-rutinoside, cyanidin-3-xyloside, cyanidin-3-glucoside acylated with malonic acid, and an unidentified acylated derivative of cyanidin-3-glucoside. Four different quantitative patterns were evident among the cultivars and selections. Total anthocyanin content ranged from 70.3 to 201 mg/100 g with a mean of 137 mg/100 g. Ten commercial blackberry juice concentrate samples were analyzed. Total anthocyanin ranged from 12.3 to 107 mg/100 g on a single-strength juice basis, and 1 sample had an atypical profile.

Thermal Resistance Parameters for Pathogens in White Grape Juice Concentrate

The heat resistance of Escherichia coli O157:H7, Salmonella, and Listeria monocytogenes that were in stationary phase, had been exposed to high osmotic pressure, or were acid adapted was evaluated in white grape juice concentrate (58°Brix, pH 3.3). The most heat-resistant cells of all three pathogens were those exposed to high osmotic pressure or in stationary phase. Unlike in single-strength juices, in concentrate the acid-adapted cells for all three pathogens were less heat resistant than were cells in the other physiological states. E. coli O157:H7 had the highest heat resistance for all temperatures tested (e.g., D62°C = 1.8±0.3 min, with a z-value of 9.9 ± 0.6°C). L. monocytogenes exposed to high osmotic pressure had the highest z-value (12.3 ± 1.2°C), although its D-values for all temperatures tested were lower (e.g., D62°C = 0.93±0.1 min) than those for E. coli O157:H7. Salmonella was the most sensitive of the pathogens under all conditions. Based on the results obtained in this study, one example of a heat treatment that will inactivate 5 log units of all three pathogens in white grape juice concentrate was calculated as 1.5 min at 71.1°C (z = 10.3°C). Validation studies confirmed the predicted D71°C for E. coli O157:H7 exposed to high osmotic pressure.