# The Influence of Processing on the Bioactive Compounds of Small Berries
## 4 Processing of Small Berries and Their Effects on Bioactive Compounds
### Pasteurization
Heat treatment performed at 84 \({}^{\circ}\)C for 2.4 min followed by HHP (480 MPa, 22 min) allowed the retention of about 92% of anthocyanins. After 3 months of storage at 6 \({}^{\circ}\)C, the contents of polyphenols and anthocyanins in strawberry pure treated by HPP (500 MPa/15 min, 50 \({}^{\circ}\)C) were higher compared to pure treated by conventional thermal pasteurization (90 \({}^{\circ}\)C, 15 min) [97]. On the other hand, some negative effects of high pressure on the total polyphenols and anthocyanins have been reported for strawberry juice and nectar [92]. Thus, it is essential to define the high-pressure conditions to obtain berry beverages with enhanced stability and bioavailability in terms of bioactive compounds. US-based technologies (ultrasonication, thermosonication, manosonication, and manothromosonication) represent promising alternative technologies for improving berry juice/puree quality while minimizing nutrient loss [98]. The pasteurization effect during US exposure is the result of acoustic cavitation and acoustic streaming, which generate  
Figure 4: The main pasteurization treatments applied for liquid and semi-solid berry products [58, 89, 92]. high local energy, high temperature, and high pressure. In addition, these US effects contribute to the disruption of the cell wall structure, promoting polyphenol release [99]. US treatment of strawberry puree was found to better retain or enhance the ascorbic acid, total polyphenols, total anthocyanins, and antioxidant activity compared to the samples treated by conventional thermal treatment [100]. Sonication treatment performed for between 10 and 30 min at 20 kHz had no effect on the antioxidant activity and anthocyanin content of raspberry puree [101]. The sonication of strawberry juice for 30 min at 20 kHz, at room temperature, increased the total polyphenic content by about 86% compared to untreated juice [102]. However, excess US treatment has a negative effect, causing the degradation of phenolic compounds by changing their structure [99]. The economic feasibility of US treatment is considered higher when combined with moderate heat and/or pressure, because it allows high-quality berry products with enhanced contents of bioactive constituents to be obtained. The pasteurization of berry liquids/semi-solids using PEF relies on the application of a high-voltage electric current for a short duration ranging from nano- to microseconds, and is dependent on field strength, pulse width, frequency, duration, and sample conductivity [55]. At electric field strength above 20 kV/cm, PEF can replace conventional thermal pasteurization while preserving nutritional and sensorial attributes [58]. Thus, PEF is considered a valid technology for producing safe liquid products with superior added value [92]. Studies performed on several berry products like bilberry and cranberry juices showed that PEF has a protective effect on anthocyanin stability [59]. In raspberry juice, PEF contributed to increasing the phenolic compound content by about 39% due to PEF's ability to release the phenolics from the vacuole of the vegetal cells, making them more bioaccessible and bioavailable [103]. [PERSON] et al. [104] reported that PEF treatment of cranberry juice combined with light-based technology allowed the retention of 88% of the anthocyanins present in untreated juice. Moreover, the pasteurization of cranberry juice by using only UV light, or high-intensity light pulses, resulted in a similar retention of polyphenols to untreated juice [104]. UV radiation processing offers the advantage of using lower temperatures than conventional thermal treatment and causes a minor reduction in heat-sensitive bioactive compounds [105]. However, the long exposure to UV light and nonuniform dose delivery were identified as limiting factors when using this treatment on a large scale, as they could exert a negative impact on the quality and nutritive value of the berry juices [106].