scholarly journals UV-C irradiation as an alternative disinfection technique: Study of its effect on polyphenols and antioxidant activity of apple juice

2016 ◽  
Vol 34 ◽  
pp. 344-351 ◽  
Author(s):  
Md Shajedul Islam ◽  
Ankit Patras ◽  
Bharat Pokharel ◽  
Ying Wu ◽  
Matthew J. Vergne ◽  
...  
2016 ◽  
Vol 23 (3) ◽  
pp. 265-276 ◽  
Author(s):  
Alifdalino Sulaiman ◽  
Mohammed Farid ◽  
Filipa VM Silva

Worldwide, apple juice is the second most popular juice, after orange juice. It is susceptible to enzymatic browning spoilage by polyphenoloxidase, an endogenous enzyme. In this study, Royal Gala apple juice was treated by thermosonication (TS: 1.3 W/mL, 58 ℃, 10 min), pulsed electric field (PEF: 24.8 kV/cm, 60 pulses, 169 µs treatment time, 53.8 ℃) and heat (75 ℃, 20 min) and stored at 3.0 ℃ and 20.0 ℃ for 30 days. A sensory analysis was carried out after processing. The polyphenoloxidase activity, antioxidant activity and total color difference of the apple juice were determined before and after processing and during storage. The sensory analysis revealed that thermosonication and pulsed electric field juices tasted differently from the thermally treated juice. Apart from the pulsed electric field apple juice stored at room temperature, the processed juice was stable during storage, since the pH and soluble solids remained constant and fermentation was not observed. Polyphenoloxidase did not reactivate during storage. Along storage, the juices’ antioxidant activity decreased and total color difference increased (up to 6.8). While the antioxidant activity increased from 86 to 103% with thermosonication and was retained after pulsed electric field, thermal processing reduced it to 67%. The processing increased the total color difference slightly. No differences in the total color difference of the juices processed by the three methods were registered after storage. Thermosonication and pulsed electric field could possibly be a better alternative to thermal preservation of apple juice, but refrigerated storage is recommended for pulsed electric field apple juice.


Author(s):  
Izabel Camacho Nardello ◽  
Rufino Fernando Flores Cantillano ◽  
Jardel Araújo Ribeiro ◽  
Gerson Kleinick Vignolo ◽  
Marcelo Barbosa Malgarim ◽  
...  

Abstract The objective of this work was to evaluate the influence of the use of UV-C radiation at an intensity of 0.53 KJ m-2, during strawberry (Fragaria x ananassa) cultivation, on the physicochemical and phytochemical parameters of the fruits. The used experimental design was completely randomized, in a single-factor arrangement with 11, 19, 29, and 39 UV-C applications and without UV-C application. The hue of the fruits was smaller at the end of the study period. pH varied in strawberries that received 39 applications of UV-C, and the soluble solids content differed with 19 applications. Antioxidant activity was lower in fruits with 11, 19, and 29 UV-C applications, whereas vitamin C content was lower only in fruits that received 29 applications. The use of UV-C radiation at an intensity of 0.53 KJ m-2, during strawberry cultivation, affects the physicochemical and phytochemical parameters of the fruits, but does not cause losses in their quality.


Molecules ◽  
2018 ◽  
Vol 24 (1) ◽  
pp. 51 ◽  
Author(s):  
Zhongxi Li ◽  
Jing Teng ◽  
Yilu Lyu ◽  
Xiaoqian Hu ◽  
Yueliang Zhao ◽  
...  

The present study examined the effect of Lactobacillus plantarum ATCC14917 fermentation on the chemical composition and antioxidant activity of apple juice. Apple juice was fermented and examined of its antioxidant activity using chemical models and cellular antioxidant assay. Furthermore, the chemical composition of fermented apple juice was characterized by LC-MS/MS. Lactobacillus plantarum ATCC14917 fermentation showed an increase in DPPH and ABTS radical scavenging activity as well as cellular antioxidant activity of apple juice. However, fermentation decreased the total phenolic and flavonoid content. Subsequent LC-MS/MS analysis of the phenolic profile indicated that the content of 5-O-caffeoylquinic acid (5-CQA), quercetin, and phloretin with strong antioxidant activity was increased significantly after fermentation. The modified phenolic composition may contribute to the increased antioxidant activity of fermented apple juice. Our findings showed that Lactobacillus plantarum ATCC14917 fermentation may be an efficient way to enhance the bioavailability of phenolic compounds and to protect cells from oxidative stress.


Horticulturae ◽  
2018 ◽  
Vol 5 (1) ◽  
pp. 1 ◽  
Author(s):  
Penta Pristijono ◽  
John Golding ◽  
Michael Bowyer

Mature green ‘Kensington Pride’ mangoes (Mangifera indica L.) were treated with a short-term UV-C light at four different intensities (0, 4.0, 8.3 and 11.7 kJ m−2). After treatment, mangoes were stored for 12 d in air (<0.005 μL L−1 ethylene) or 0.1 μL L−1 ethylene at 20 °C and 100% relative humidity (RH). Weight loss, peel colour, firmness, ethylene production, respiration rate, total soluble solids (TSS), titratable acidity (TA), total chlorophyll content, total phenolic content (TPC) and total antioxidant activity were assessed at 3-d intervals. The results showed that UV-C treatment delayed skin degreening, reduced endogenous ethylene production, suppressed respiration rate and lowered chlorophyll content compared to untreated control fruit. Fruit treated with UV-C had significantly higher TPC and total antioxidant activity at the end of the storage period than untreated fruits for both storage atmospheres. In addition, UV-C treated fruits remained significantly firmer than untreated fruits. UV-C treatment significantly affected TSS and TA levels in different ways. Storage of fruits in 0.1 μL L−1 ethylene significantly affected fruit firmness, respiration rate and ethylene production, while other fruit quality parameters were similar to fruit stored in air. These results indicated that UV-C irradiation could be used as an effective and rapid method to extend the postharvest life of mature green mangoes without adversely affecting certain quality attributes in the presence of low-level ethylene during storage.


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