Search Results (4)

The aim of this study was to investigate the influence of high intensity pulsed electric field (HIPEF) technology on the stability of total phenols, anthocyanins, hydroxycinnamic acids, flavonols, and condensed tannins in strawberry juices (Fragaria x ananassa Duch. cv. ‘Albion’) with different ripening stages (75% and 100%) and stored at +4 °C for 7 days. The HIPEF parameters studied were: (i) electric field strength (40 and 50 kV cm⁻¹), (ii) frequency (100 and 200 Hz), and (iii) treatment duration (3 and 6 min). Of the HIPEF parameters studied, electric field strength and frequency had a statistically significant effect on the content of all phenolic compounds. Treatment duration showed no statistically significant effects on phenolic compounds except for flavonols and condensed tannins. Storage had a positive effect on the stability of most of the phenolic compounds, with the exception of flavonols. Optimization of HIPEF processing showed that strawberry samples at both ripeness levels were suitable for HIPEF treatment to obtain functional fruit juices with a high content of polyphenols. Full article

The health benefits of fruit juices have been associated with their high content of antioxidant compounds. Commercial juice has been traditionally heat-processed to destroy microorganisms and enzymes. However, high temperatures induce undesirable changes in the nutritional value of the juice. High-intensity pulsed electric fields (HIPEF) are being studied as an alternative to heat treatments. In addition, in vitro and in vivo methods have been recommended to determine the antioxidant potential of juices in a complementary manner. Thus, the antioxidant activity of untreated, high-intensity pulsed electric fields (HIPEF) or heat-treated fruit juices (tomato, apple, pineapple and orange) was studied using in vitro (TEAC, DPPH, FRAP and Folin-Ciocalteu) and in vivo assays (Saccharomyces cerevisiae). Vitamin C and total phenolic compounds in these juices were determined. The highest antioxidant activities (12.01 mmol of Trolox/L) were obtained through the Folin-Ciocalteu assay in orange juices. The lowest values (0.119 mmol of Trolox/L) were found in apple juice analysed by the FRAP assay. Vitamin C content varied from 10 mg/L (orange juice) to 344 mg/L (orange juice). The highest concentration of total phenolic compounds was determined in orange juice (1238 mg/L), whereas the lowest value was found in tomato juices (149 mg/L). The effect of HIPEF and thermal processing on the antioxidant potential of juices depended on the fruits used to prepare the juices and the antioxidant activity assay conducted. Vitamin C concentration was directly related to the antioxidant activity analysed by Folin-Ciocalteu and FRAP methods and the S. cerevisiae growth rate. S. cerevisiae yeast can be used as a feasible in vivo assay to further determine the antioxidant activity of fruit juices. Full article

The effect of high-intensity pulsed electric fields (HiPEF) has been reported on the microbial resistance of fruit juices and beverages. However, the influence of HiPEF on bioactive compounds in herbal infusions is still limited. The objective of the present work was to evaluate chemical stability of polyphenols of infusions from Buddleja scordioides or Salvilla under thermal processing (concentrates) followed by HiPEF treatments. Buddleja infusions were prepared at 1% w/v of salvilla, heated, filtered and concentrated in a thin falling film evaporator. Three different HiPEF treatments were applied to Buddleja scordioides concentrated beverages. The percentage of pulse rate was 25 and 90%; output temperature, 18.3 ± 1 °C; and the frequency range, 100, 300 and 400 Hz. The feed flow was 0.5 L/h. DPPH radical scavenging assay, inhibition of Nitric Oxide activity and analysis of phenolic acids and flavonoids by UPLC-ESI-MS/MS were determined. ANOVA one-way analysis and Tukey test (p < 0.05) were used to analyze results. Concentration process increases the amount of flavonols; however, the use of HiPEF produces a minor reduction on antioxidant capacity. The use of HiPEF at 1000 kJ/kg and 1100 kJ/kg displays a similar profile on phenolic acids between HiPEF-treated beverages and concentrates, showing that the use of HiPEF may be a promissory technology in the processing practices of herbal infusions. Full article

Eating habits of western populations are changing due to modern lifestyles. As a result, people are becoming more susceptible to chronic and degenerative diseases. This fact has motivated the food industry to develop functional products that could decrease the incidence of those disorders. It is well known that fruit juices, milk and soymilk possess high concentrations of antioxidant and bioactive substances. Hence, the development of these functional beverages is a potential way to take advantage of their nutritional properties and exotic flavors that could attract the interest of consumers. At the same time, application of the right preservation treatment is of high relevance in order to obtain safe products with convenient shelf life and high concentration of health-related compounds. This fact represents a great challenge that scientists and technologists are currently facing. Today, novel preservation processes such as high hydrostatic pressure (HHP), high intensity pulsed electric fields (HIPEF) and ultrasound (US), among others, are being evaluated as an alternative to heat pasteurization, obtaining promising results. Hence, this review gathers the most relevant information about the development of mixed beverages containing fruit juices and milk or soymilk. Furthermore, the advantages and drawbacks of the application of non-thermal treatments for functional beverages’ preservation with high content of bioactive compounds are also mentioned. Full article