Comparative Study of the Effects of Ultraviolet Light and High Hydrostatic Pressure on the Quality and Health Related Constituents of Wheatgrass Juice
The perceived health benefits of low acid juices have resulted in increased demands for vegetable beverages such as wheatgrass. The following reports on a comparative study to evaluate Ultraviolet Light UV-C or High Hydrostatic Pressure HHP as alternative non-thermal methods for wheatgrass juice. A thermal treatment of wheatgrass at 75°C for 15s was included as control. Pressure treatments of 500MPa and 600MPa for 60, 90 and 180s supported 5-log CFU reduction of bacteria inoculated into wheatgrass juice. To achieve the same level of bacterial inactivation, a UV dose of 25.4mJ/cm2 at 254 nm was required. The UV and HHP treatments significantly increased the chlorophyll of juice. Both HTST and HHP treatments resulted in negligible losses in antioxidants, but UV preserved TPC and antioxidants. HHP treatment did not have a significant reduce in color and enzymes levels. The study illustrated that HHP would be preferred non-thermal treatment for treating wheatgrass juice.