Search results for "UIC"
showing 10 items of 929 documents
PCR-fingerprinting and RAPD approaches for tracing the source of yeast contamination in a carbonated orange juice production chain.
2005
Aims: To investigate the sort and the origin of the contamination of a packed fruit juice. Methods and Results: Fifty-eight yeast isolates were collected in a survey of two different visits to a carbonated orange juice factory. In each visit, samples were collected, six times, from seven points in the production chain. For each visit, no significant differences were observed among the yeast average values obtained in the control points considered. The random amplified polymorphic DNA (RAPD) with primer P24 and the PCR-fingerprinting with the microsatellites primers (GTG)5 and (GAC)5 were used, in order to discriminate the isolates, rendering 29 composite profiles; the most frequent one (24/…
Color of orange juice treated by High Intensity Pulsed Electric Fields during refrigerated storage and comparison with pasteurized juice
2008
Abstract High Intensity Pulsed Electric Field (HIPEF) is one of the nonthermal minimal processing technologies interesting for scientists and food industry as a new, alternative (preservation) process for liquid food. We have evaluated the effect on color, browning and hydroxymethylfurfural (HMF) of a pasteurized orange juice and the same orange juice treated by HIPEF, during 7 weeks stored in refrigeration at 2 °C and 10 °C. Pasteurized orange juice presents greater yellow tendency ( b ∗ ) and less red tendency ( a ∗ ) than the untreated orange juice, while HIPEF orange juice presents a coloration more similar to the untreated orange juice. Color variations (Δ E ) during storage are greate…
ORAC and TEAC assays comparison to measure the antioxidant capacity of food products
2009
Abstract Oxygen radical antioxidant capacity (ORAC) and trolox equivalent antioxidant capacity (TEAC) assays were compared to estimate the total antioxidant capacity (TAC) of orange juice, milk, and an orange juice-milk beverage. When the TEAC method was used with this beverage, an increase in the concentration of orange juice corresponded to an increase in TAC, but increasing the percentage of milk did not increase the TAC value. When the ORAC method was applied, it was seen that increased concentrations of juice or milk corresponded to greater antioxidant capacity. An evaluation was also made of the influence of certain compounds (ascorbic acid, gallic acid, β-carotene, lutein, zeaxanthin…
Effects of thermal treatments on pectinesterase activity determined in blood oranges juices
2005
Abstract The citrus processing industry aims to maintain turbidity and attractive colour of the juice obtained from Sicilian blood oranges. Nevertheless, the presence of pectinesterase (PE, E.C. 3.1.1.11) causes the loss of these peculiar characteristics, due to precipitation of colloids and very fine pieces of pulp in suspension, with negative effects on colour and clarification of the juices. This study compares total PE activity of Sicilian blood oranges ( Sanguinello , Moro , Tarocco ) with the blonde cultivar Navel , checking enzyme stability with various pasteurisation times and temperatures conditions. Decimal reduction time and temperature ( D and z ) as well as the kinetic constant…
In vitro culture of albedo tissue from fruits of Citrus sinensis cv. Washington Navel: Effect of fruit age and orange juice
1994
SUMMARYCallus from citrus fruit explants has been used to study different aspects of fruit physiology. However, growth responses of callus derived from citrus fruit tissues are not always comparable with those of intact fruit; there are, for example, differences in nutritional requirements. Results with tissues cultivated in vitro seem to depend on a variety of environmental and internal factors. In the present work albedo tissue from fruits of Citrus sinensis cv. Washington Navel of different age has been used as a source of explants. The growth (fresh weight) of the calli was dependent on the age of the fruit from which the explants were taken, as well as on the addition of orange juice t…
EFFECT OF PLANT GROWTH REGULATORS AND ORANGE JUICE ON GROWTH OF CALLUS FROM FRUIT TISSUES OF WASHINGTON NAVEL ORANGE
1997
The effect of the plant growth regulators kinetin, gibberellic acid (GA3), and 2,4- dichlorophenoxyacetic acid (2,4-D), either alone or in combination with orange juice, on the in vitro growth of mesocarp and endocarp explants from 90–120 day-old Washington Navel Citrus sinensis orange fruits has been determined. Both fruit tissues formed callus. From endocarp 100% callus was formed in all cultures, even without growth regulators in the culture medium, while callus growth was lower from mesocarp. The addition of orange juice at a final concentration of 15% (v/v) to the basal medium without growth regulators increased the callus growth, specially that derived from endocarp. However, the high…
Incidence of microorganisms from fresh orange juice processed by squeezing machines
2012
Abstract This study was carried out to evaluate the microbiological quality of orange juice obtained from squeezing machines in foodservice establishments. The samples included fresh squeezed orange juice and juice which is maintained in metal jugs until consumption. According to the European Commission Regulation (No. 2073/2005 and No. 1441/2007) and Spanish microbiological criteria (No. 3484/2000), 12% and 43% of the total examined lots exceed the adopted limits of mesophilic aerobic counts and Enterobacteriaceae, respectively. Possibly, this contamination is caused by incorrect handling of oranges and juices and also by inadequate cleaning and sanitization of squeezing machine and metal …
Product information, hedonic evaluation, and purchase decision: an experimental study of orange juice
2007
AbstractTwo randomly sampled groups of subjects were endowed with real budgets and placed in 5 different budget/price situations. In each situation they had to evaluate 6 orange juices and complete a demand table. At the end of the experiment, one demand table was randomly selected and participants had to buy the corresponding products. In one group, participants choose after looking at the packaging in the other they could also taste the products. Results show that participants who chose without tasting, made quicker decisions, selected a larger number of variants and were more influenced by prices than those who could taste the products. Although choices appeared very heterogeneous, most …
Anteroxanthin concentration during refrigerated storage in orange juice treated by PEF
2009
Pulsed Electric Field (PEF) processing inactivates microorganisms without significant adverse effects on flavor and nutrients. In this work was studied the transformations of antheraxanthin and mutatoxanthin when natural orange juice is treated by pasteurisation (90°C, 20 s) or PEF (30 kV/cm, 100 µs), and also its evolution during seven weeks of storage in refrigeration at two different temperatures (2°C and 10°C). The results showed that antheraxanthin concentration decreased during the storage. The decrease was greater in the untreated, pasteurised and PEF-treated orange juices stored at 10°C and this carotenoid was not detected from the 6 th week onwards. The same result was observed in …
Degradation of carotenoids in orange juice during microwave heating
2010
Degradation of carotenoids in orange juice was monitored during microwave (MW) heating at different time/temperature conditions. Various carotenoids were identified and quantified by HPLC. Degradation rate of carotenoids was influenced by MW heating temperatures: at 60 degrees C and 70 degrees C for 10 min violaxanthin and antheraxanthin were the compounds most unstable, while lutein and provitamin A carotenoids were more stable. At 85 degrees C a decrease of about 50% was observed for almost all carotenoids after 1 min of MW heating. Temperature sensitivity (z value) for total carotenoids was 14.2 degrees C, for single compounds z values ranged between 10.9 degrees C for beta-carotene and …