Effect of high‐pressure processing on immunoreactivity, microbial and physicochemical properties of hazelnut milk

Abstract

Summary This study investigated the effects of high‐pressure processing (HPP) and thermal processing (TP) on the overall quality attributes of hazelnut milk. HPP achieved the same microbial safety as TP, and the pH, °Brix and sugar contents were maintained at the levels of fresh hazelnut milk. Although HPP caused colour changes, the ∆E was smaller than that of the TP sample. Increasing pressure significantly decreased the immunoreactivity of the hazelnut milk by 70%, while simultaneously reducing the levels of essential and non‐essential amino acids and chemical score (CS) and the essential amino acid index (EAAI) values. However, neither HPP nor TP significantly affected the fatty acid composition of hazelnut milk. HPP retained higher total phenolic and flavonoid levels of the hazelnut milk, with a better antioxidant capacity than TP samples. Thus, the HPP maintained microbial safety during cold storage, and physicochemical properties of the treated hazelnut milk were not significantly different from those of the fresh hazelnut milk.

“Technological convergence” of preventive nutrition with non thermal processing

“…In almond milk, both TPC and TFC increased after PEF (28 kV/cm) treatment (Manzoor et al, 2020). Similar results were reported for bioactive compounds in hazelnut milk (Tsai et al, 2018) and fruit‐based soy milk (Morales‐de la Peña et al, 2010). It is generally thought that PEF‐induced alterations in the voltage‐gated ion channels lead to a rapid influx of Ca 2+ into the cell membrane thus increasing its permeability.…”

“…In addition to microbially safe and stable food products, HPP improves the functionality of various important bioactive compounds such as antioxidants which are normally lost with the application of heat (Tsai et al, 2018). Both anthocyanin and TPC increased in blueberry samples at first but eventually decreased during storage.…”

“…With the application of high pressure (200–600 MPa), HPP can induce microbial decontamination as efficiently as TP, without the need for high temperatures. In addition to microbially safe and stable food products, HPP improves the functionality of various important bioactive compounds such as antioxidants which are normally lost with the application of heat (Tsai et al, 2018).…”

Microbial Shelf-Life, Starch Physicochemical Properties, and In Vitro Digestibility of Pigeon Pea Milk Altered by High Pressure Processing

“…In another study, it was observed that with a combination of high pressure and mild thermal treatment (75 • C), HPP altered the isoflavone profiles of soymilk through promoting a shift in the isoflavone profile from malonylglucosides toward β-glucosides [17]. Tsai et al [18] investigated the effects of HPP on the quality attributes of hazelnut milk during refrigerated storage, and found that HPP at 600 MPa for 5 min achieved the same level of microbial safety as thermal processing at 80 • C for 3 min and significantly decreased immunoreactivity without significantly changing the physicochemical properties of the hazelnut milk. In the present study, a pasteurization experiment was performed with HPP conditions that enabled a 5-log reduction of E. coli O157:H7, namely 200 MPa/240 s, 400 MPa/210 s, and 600 MPa/150 s. Results indicated that the inhibition of TAB, psychrotrophs, and E. coli/coliforms in HPP-treated samples were not significantly different compared to the HTST-treated samples up to 21 days of refrigerated storage.…”

Novel technologies to improve food safety and quality

“…Despite the great advances achieved during the last decades, HHP keeps being evaluated to assure safety in novel foods such as hazelnut milk [27], chokeberry juice [28], cucumber juice, mango nectar [29] and prickly pear juice [30]. Overall, HHP has the same efficacy as conventional pasteurization without modifying nutritional and sensory properties of the product.…”