# Non-Thermal Technologies in Food Processing: Implications for Food Quality and Rheology
## 2 Pulsed Electric Field (PEF)
pasteurisation in terms of their effects on the microbial shelf life and quality of orange juice at 4 \({}^{\circ}\)C and 22 \({}^{\circ}\)C. They reported that the HIPEF treatment (35 kV/cm for 1000 us) was microbiologically stable for 56 days when under refrigeration, whereas spoilage occurred within 30 days at room temperature. Under both storage conditions, the HIPEF-treated orange juice had better colour retention compared to heat pasteurisation (90 \({}^{\circ}\)C for 1 min). Notably, HIPEF-treated juice had significantly higher amounts of vitamin C, meeting daily needs for 56 days of cold storage, whereas heat treatment led to a drastic loss of vitamin C after 14 days (25.2-42.8%) [69]. In addition, PEF has been shown to improve the extraction of bioactive compounds such as polyphenols from fruits and vegetables, which enhance the nutritional and functional properties of the treated foods [70]. [PERSON] et al. [71] reported that the PEF-assisted extraction of the nutritionally valuable and antioxidant components from papaya peels at 4 kV/cm and 400 pulses yielded total polyphenols (85%) compared to the raw peel sample (75%). Likewise, [PERSON] et al. [72] found that PEF treatment at a field strength of 0.75 kV/cm and 600 us, resulted in the maximum yield of total steroidal alkaloids (1856.2 ug/g dried potato peels) which was 99.9% higher than that of the untreated peels. Notably, while the PEF enables the extraction of bioactive compounds, it does not cause a major change in the texture or structural integrity of liquid foods [66]. In solid foods, though, electroporation due to PEF may lead to softening due to cell membrane breakdown, which can be beneficial for the subsequent processing steps such as drying [65]. This controlled modification does not impact the overall rheological stability, but rather optimises the food matrix for an enhanced bioavailability of nutrients. This results in increased stability and homogeneity, which is crucial for improved quality and consumer acceptance. Using the PEF for processing ensures that bioactive compounds, including vitamins and antioxidants, remain largely intact, thus enhancing the nutritional profile of the treated products. For example, the antioxidant activity in fruit juices treated with PEF is higher than in products processed with conventional thermal treatments, which assures a better taste and health benefits [6; 52; 70]. In addition, a PEF can inactivate spoilage enzymes such as polyphenol oxidase in juices, thus extending the shelf life and improving product stability [2]. These advantages make a PEF suitable for producing high-quality, fresh-like foods with an extended shelf life [61; 64]. The effect of PEF on the rheological properties of the dough and bread quality have also been reported. In the study by [PERSON] et al. [73], yeasts that were treated with a PEF under optimal conditions exhibited a higher magnesium content, and this led to a 50% increase in the level of magnesium in bread compared to the control samples. Notably, the PEF-treated yeasts did not alter the overall chemical composition of the bread, but significantly affected its technological properties. Treated samples had a greater moisture content (54.03 \(\pm\) 0.29%), which contributed to lowering the total baking loss, thus improving the overall baking efficiency and product quality. These findings indicate the capability of PEF not only in microbial inactivation, but also in functional ingredient enrichment in bakery products, widening its application scope in the food industry [73]. Another study by [PERSON] et al. [74] demonstrated that the use of PEF at 12 kV/cm for 162 ms significantly inhibited the activity of \(\beta\)-glucanase by up to 76.5%, increasing the content of total \(\beta\)-glucanas (33.5%) and water-extractable arabinoxylans (36-41%).