Effects of Ultraviolet Light and High‐Pressure Processing on Quality and Health‐Related Constituents of Fresh Juice Products

Abstract

Fresh juices are highly popular beverages in the global food market. They are perceived as wholesome, nutritious, all-day beverages. For a fast growing category of premium juice products such as cold-pressed juices, minimalprocessing nonthermal techniques such as ultraviolet (UV) light and high-pressure processing (HPP) are expected to be used to extend shelf-life while retaining physicochemical, nutritional, and sensory characteristics with reduced microbial loads. Also, UV light and HPP are approved by regulatory agencies and recognized as one of the simplest and very environmentally friendly ways to destroy pathogenic organisms. One of the limitations to their more extensive commercial application lies in the lack of comparative effects on nutritional and quality-related compounds in juice products. This review provides a comparative analysis using 92 studies (UV light: 42, HPP: 50) mostly published between 2004 and 2015 to evaluate the effects of reported UV light and HPP processing conditions on the residual content or activity of bioactive compounds such as vitamins, polyphenols, antioxidants, and oxidative enzymes in 45 different fresh fruit and vegetable juices (low-acid, acid, and high-acid categories). Also, the effects of UV light and HPP on color and sensory characteristics of juices are summarized and discussed.

Feasibility of a Novel Industrial-Scale Treatment of Green Cold-Pressed Juices by UV-C Light Exposure

“…However, there was no clear difference between the treated and untreated juice samples that could be detected by eye. Previous studies have shown UV-C to have an insignificant effect on the colour parameters of fruit juices [4]. Watermelon, orange, and apple juices treated with UV-C energies up to 100 kJ L −1 retained their colour attributes and, in some cases, better preserved their colour during storage than untreated juices [4].…”

“…Samples were measured in triplicates and results was expressed as values of L*, a*, b*, and ∆E for darkness/brightness, redness/greenness, yellowness/blueness, and total colour difference, respectively. A colour difference scale based on ∆E values (not noticeable = 0 to 0.5, slightly noticeable = 0.5 to 1.5, noticeable = 1.5 to 3.0, well noticeable = 3.0 to 6.0, greatly noticeable = 6.0 to 12.0) was adapted from Koutchma et al (2016) [4].…”

“…UV-C treatments ranging from 0.2-3.6 kJ L −1 have led to 1.0-3.0 log reductions in these microorganisms in fruit juices. However, the effectiveness of the treatment varies due to factors such as juice clarity, energy/fluence, and design of the UV-C unit [4]. Commercial units such as the SurePure UV-C reactor have achieved log reductions of 2-7 for yeasts in treated grape juice and wines [12].…”

A review on mechanisms and commercial aspects of food preservation and processing

“…This process also inactivates spoilage of foods, delays the onset of chemical and enzymatic deteriorative processes, and retains the important physical and physiochemical characteristics of foods. HHP has the potential to serve as an important preservation method without degrading vitamins, flavors, and color molecules during the process [58,103,104]. Freshness and improved taste with high nutritional value are the peerless characteristics of HPP technology.…”

“…Under this method, food products are preserved as pickles, relishes, etc. [104]. Vinegar fermentation results in acetic acid and water by oxidation of alcohol [114] Lactic acid fermentation takes place due to the presence of two types of bacteria: homofermenters and heterofermenters.…”