Search results for "Juice"
showing 10 items of 192 documents
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 …
Carotenoid Profile Modification during Refrigerated Storage in Untreated and Pasteurized Orange Juice and Orange Juice Treated with High-Intensity Pu…
2006
A comparative study was made of the evolution and modification of various carotenoids and vitamin A in untreated orange juice, pasteurized orange juice (90 degrees C, 20 s), and orange juice processed with high-intensity pulsed electric fields (HIPEF) (30 kV/cm, 100 micros), during 7 weeks of storage at 2 and 10 degrees C. The concentration of total carotenoids in the untreated juice decreased by 12.6% when the juice was pasteurized, whereas the decrease was only 6.7% when the juice was treated with HIPEF. Vitamin A was greatest in the untreated orange juice, followed by orange juice treated with HIPEF (decrease of 7.52%) and, last, pasteurized orange juice (decrease of 15.62%). The decreas…
Changes of colour and carotenoids contents during high intensity pulsed electric field treatment in orange juices
2005
Abstract Liquid chromatography (LC) was the method chosen to evaluate the effects of high intensity pulsed electric fields (HIPEF), with different electric field intensities (25, 30, 35 and 40 kV/cm) and different treatment times (30–340 μs), on orange juice cis / trans carotenoid contents. In parallel, a conventional heat treatment (90 °C, 20 s) was applied to the orange juice in order to compare the effect on the carotenoid contents. HIPEF processing of orange juice is an alternative to the thermal treatment of pasteurization, provided that it is kept refrigerated, because, when the most extreme conditions of this kind of treatment are applied, the decrease in the concentration of caroten…
Erosive effect of industrialized fruit juices exposure in enamel and dentine substrates: An in vitro study
2021
Background Erosive tooth wear has been a highly prevalent and emerging phenomenon related to eating habits of the population. Aim: This study sought to investigate industrialized fruit juices exposure in enamel and dentine substrates in terms of erosive effect. Material and methods Human enamel and dentine specimens were randomized into 8 groups (n=8): Grape juice - Ades®, Grape juice - Del Valle Kapo®, Grape juice - Aurora®, Orange juice - Del Valle Kapo®, Orange juice - Ades®, Strawberry juice - Mais Vita®, Strawberry juice - Ades®, Citrus fruit juice - Tampico®. Specimens were submitted to an in vitro erosive challenge and to a microhardness test to evaluate the percentage of surface mic…
Inactivation kinetics of pectin methyl esterase under combined thermal–high pressure treatment in an orange juice–milk beverage
2008
Abstract The inactivation kinetics of PME in an orange juice–milk beverage system treated by thermal (65–80 °C) and combined thermal (25–65 °C)–high pressure (0.1–700 MPa) processes were fitted using a biphasic model. About 6–8% of the initial activity corresponding to the heat and pressure stable fraction was observed. For complete inactivation a treatment at 90 °C, 1 min or 700 MPa at 55 °C for 2 min was necessary showing the protective effect of the orange–milk media. The extent of inactivation was different in the orange matrices showing that PME was more thermostable in the orange juice–milk based beverage system as compared to the purified enzyme in a buffer system. On the other hand,…
Erratum: Bosch-Sierra, N., et al. Effect of Fibre-Enriched Orange Juice on Postprandial Glycaemic Response and Satiety in Healthy Individuals: An Acu…
2021
The authors have requested that the following changes be made to their paper [...]
The quality of orange juice
2013
Mild processing technologies allow to obtain OJ available year-round, with characteristics closer to those of fresh orange, namely for its content in substances exhibiting free radical scavenging and antioxidant activities. These healthy components, mainly vitamin C, carotenoids and flavonoids, exhibit different absorption kinetics, bioavailability and antiradical mechanisms. Anyway, there is greater absorption of these nutrients when taken not as singly as supplements, but when consumed in minimally processed fruit, such as OJ, in which they naturally appear along with all the other biologically active phytonutrients that citrus fruits contain. Type of processing, packaging and storage con…
Comparison of stir bar sorptive extraction in the liquid and vapour phases, solvent-assisted flavour evaporation and headspace solid-phase microextra…
2017
The volatile fraction plays an important role on the organoleptic properties and overall acceptability of fruit juices. This work reports for first time a non-targeted approach for the analysis of the volatile fraction of fruit juice by stir bar sorptive extraction (SBSE[1]) in liquid and vapour phase (HSSE[2]) at three extraction times (30, 60, and 120 min), two temperatures (room temperature and 40 °C), and two sample volumes (5 and 10 mL). The resultant volatile profiles were compared with solvent-assisted flavour evaporation (SAFE[3]) and headspace solid-phase microextraction (HS-SPME[4]). SBSE and HSSE enabled the detection and identification of more compounds than HS-SPME and less tha…
Full inhibition of enzymatic browning in the presence of thiol-functionalised silica nanomaterial
2018
[EN] Darkening processed fruits and vegetables is caused mainly by enzymatic browning through polyphenol oxidase (PPO) action. Accordingly, we explored the potential of four silica-based materials (MCM-41 nanometric size, MCM-41 micrometric size, UVM-7 and aerosil), non-functionalised and functionalised with thiol groups, to inhibit PPO activity in the model system and apple juice. All materials showed relevant performance when immobilising and inhibiting PPO in model systems, and support topology is a main factor for enzyme immobilisation and inhibition. Thiol-containing silica UVM7-SH showed the greatest inactivation, and similar browning values to those obtained by acidification. The enz…
Influence of the functionalisation of mesoporous silica material UVM-7 on polyphenol oxidase enzyme capture and enzymatic browning
2020
Polyphenol oxidase (PPO), also known as tyrosinase and catechol oxidase, is the enzyme responsible for enzymatic browning in foods. It causes undesirable organoleptic, nutritional and colour changes. Here, we report the preparation of five nanomaterials and a study of their ability to modulate PPO enzyme activity. The materials consist of UVM-7 supports (a mesoporous silica material) modified with diverse functional groups (i.e. amine, carboxylic acid, isocyanate, alkane and pyridine). We also studied the PPO immobilisation capability of the materials. All the materials, except the carboxylic acid functionalised one, offer high PPO loading capabilities and the immobilisation speed increases…