Impact of blue-LED as a non-thermal preservation technology on bio-active compounds, quality parameters, microbial and enzymatic spoilage of guava juice

Abstract

Even though pasteurization is commonly practiced and efficient in inhibiting the growth of microorganisms in fruit juices, there is a desire for non-thermal processes that retain the nutrients and sensory attributes of the juices. Therefore, this study aimed to produce healthy guava juice with high bioactive compounds using LED technology (T1: treated with blue wavelength 445 nm for 10 min and T2: treated with blue wavelength 445 nm for 30 min), compared to C: control (juice without treatment) and T3: pasteurized juice (at 90 °C for 60 s). All samples were evaluated during storage at 5 °C for 2 weeks. The results found that T2 was the superior processing method that maintained the juice's bioactive compounds, such as vitamin C, total phenol, and antioxidants, which reached 37.54 and 15.54 mg/100 mL; 30.46 and 17.89 mg/100 mL and 65.98 and 13.33 % in the T2 and C juice samples, respectively. In addition, LED treatments maintained sensory characteristics (taste, odor, and color) with no significant difference from the control sample, without an aftertaste at zero time, and extended the shelf life for over 14 days, as indicated by the microbial load, which did not exceed the acceptable limit (6 Log CFU/g). Additionally, the T3 recorded no microbial growth, enzymatic activity, and optimal preservation of vitamin C, compared to the control, which showed a gradual degradation of vitamin C. reaching 15.45 mg/100 mL (p < 0.05). Therefore, LED technology could be a promising non-thermal food preservation technique for producing high-quality, healthy products with a long shelf-life and low production costs.