Development of a tangerine-orange juice added with yerba maté (Ilex paraguariensis) extract and processed by UV-C light

FERRARIO, MARIANA; GUERRERO, SANDRA; FENOGLIO, DANIELA; SCHENK, MARCELA

Londres

Conferencia; 22nd Euro-global summit on food and beverages; 2019

UV-C light (254nm) assisted by other stress factors may be a good alternative to traditional thermal treatment for reducing microbial contamination in turbid juices, thus overcoming the UV-C processing limitations imposed by suspended matter which can harbor microbial cells. YM has been largely studied due to antioxidant and antimicrobial properties, among others, attributed to its phenolic compounds (PC). The aim of this study was to develop a tangerine-orange juice (1:1, pH:3.9±0.1, 11.6±1.0°Brix, 1309±20 NTU, absorption coefficient:0.41 %v/v, D3,2: 24.0±1.4 µm, D4,3: 330.0±27.7 µm) processed by UV-C (0.87m-long annular reactor, 2 serially connected UV-C lamps; 30 watts, 1.8 L/min; 15min; 13.1 kJ/m2; 20°C) added with yerba mate extract (YME). For the YME, leaves were sonicated (20kHz; 95.2µm; ethanol; 25°C), freeze-dried and subsequently added to the juice (0.4 %w/v). UVC/H+YME treated samples were periodically examined for native flora. PC by Folin-Ciocalteau reaction, flavonoid content (FC), total antioxidant activity (TAA) by DPPH and ABTS, color (CIELab values), turbidity, °Brix and pH were also assessed before and after treatment. Unprocessed juice with or without YME (controls) exceeded the recommended limit for total coliforms since day 0 of storage. UV-C treatments was highly effective as it reduced native flora by 4.0- 5.1 logs whitout being able to recover during 15 days of storage. FC, PC TAADPPH, TAAABTS were increased up to 4.0, 2.0, 1.5 and 2.1 times after YME addition of processed juice, respectively, compared to control juice (FC= 0.15±0.06 mg Catequin Eq/mL, TAADPPH= 3.69±0.14 mg Trolox Eq/mL, TAAABTS=0.58±0.40 mg Trolox Eq/mL, PC=0.63±0.10 mg GAE/mL). UV-C+YME treated juice showed higher turbidity, °Brix and lower a* values, indicating that samples were less red, but greener than control; whereas, pH was not altered by the treatment.Consumer profiling studies revealed that the UVC/H+YME treated juice was well accepted by a group of consumers interested in sour products with herbal taste and strong aroma. This study expands the use of UV-C processing to turbid systems obtaining promising results as regards to the development of an innovative beverage.