Potential Of High Pressure Processing Research Articles

Mechanistic insights into changes in endogenous water soluble pectin and carotenoid bioaccessibility in mango beverage upon high pressure processing

High hydrostatic pressure (HHP) (300/400/500 MPa for 5 min) and high pressure homogenization (HPH) (50/100 MPa for 1 pass) were applied to mango beverage to explore their effects on water soluble pectin (WSP) and bioaccessibility of total carotenoids (BAC), and the relationship between BAC and modified WSP. Compared to untreated sample, HPH at 50 and 100 MPa combined with/without HHP pronouncedly increased the WSP and galacturonic acid (GalA) concentrations in mango beverage and the molecular weight (Mw) of WSP, decreased the degree of methylesterification (DM) of WSP, and affected other structural indicators of WSP to various extent, while alone HHP slightly increased the GalA concentration in mango beverage and the Mw of WSP. These changes induced by high pressure processing were mainly due to mechanical release and solubilization of the pectin embedded in cell wall with higher Mw, shorter/fewer side chains, and lower DM. HPH had more pronounced effects on WSP than HHP due to stronger mechanical force. Compared to untreated sample, HPH at 50 MPa and HHP had no significant effect on BAC, while HPH at 100 MPa significantly increased the BAC by 32.22% and HPH (100 MPa) +HHP increased the BAC by 38.65%–76.32%. The BAC showed positive binomial correlations with GalA and WSP, and upwards binomial correlations with the Mw of WSP and viscosity of mango beverage. Moreover, a statistical negative correlation was found between the BAC and DM. Results highlighted the potential of high pressure processing to regulate the BAC by modifying WSP and affecting WSP-carotenoids interactions.

High pressure processing of tamarind (Tamarindus indica) seed for xyloglucan extraction

Tamarind seed xyloglucan was extracted from tamarind kernel powder by applying high pressure processing and a conventional method. The main objective was to investigate the potential of high pressure processing for the extraction of tamarind seed xyloglucan compared to conventional method. The composition, color, viscosity, water absorption index, water solubility index, molecular weight, and xyloglucan identity of the extracts were analyzed. High pressure processing at 250–500 MPa provided extraction yields between 51.6 and 53.0% while that of the conventional method was 46.4%. The SEM micrographs of the defatted tamarind kernel powder residuals collected after high pressure extraction at 250 and 500 MPa had a smooth surface with no porous microstructure. The viscosity and weight average molecular weight values of xyloglucan powders produced using high pressure extraction were between 42-70% and 20–43% compared to those using conventional method. The SEC, FT-IR and HPLC analysis results demonstrated that the main carbohydrate were xyloglucan with 92.0–96.8% of xyloglucan relative to the Megazyme xyloglucan standard examined from FT-IR results.

Potential of high-pressure processing and high-temperature/short-time thermal processing on microbial, physicochemical and sensory assurance of clear cucumber juice

Clear cucumber juice, clarified by ultra-filtration (UF), was treated by high-pressure processing (HPP, 500 MPa/5 min) and high-temperature/short-time thermal processing (HTST, 110 °C/8.6 s), and stored at 4 °C. UF significantly decreased total aerobic bacteria (TAB) and yeasts and molds (Y&M) in the juice by 1.35 ± 0.11 and 1.94 ± 0.02 log cycles, respectively, increased juice clarity to 99.85 ± 0.07%, and did not change pH, titrable acidity (TA) and four key aroma compounds of (Z)-6-nonenal, (E,Z)-2,6-nonadienal, (E)-2-nonenal, and (E,Z)-3,6-nonadien-1-ol. Following the UF, TAB and Y&M in the juice were reduced by HPP or HTST to be < 1 log cycle, and showed no outgrowth after refrigerated storage of 20 days. HPP-treated juice showed less total color change, higher clarity and retained more key aroma compounds than HTST-treated juice. Moreover, sensory evaluation suggested that HPP-treated juice always showed higher scores for overall acceptability than HTST-treated juice. The combination of HPP and refrigeration could be used as an alternative to produce high quality clear cucumber juice with a shelf-life of 20 days. Industrial relevance Consumption of fresh vegetable juices, as a low-sugar and calorie alternative to fruit juices, is becoming increasingly popular. The objective of this work is to use ultra-filtration membrane to develop clear cucumber juice, which are not commercially available on the market in China. And further to explore the possibility of high pressure processing (HPP) plus refrigeration on quality assurance of clear cucumber juice. Findings of this study could help processors commercialize this technology in developing clear fruit and vegetable juices using non-thermal processing to replace current thermal processing.

A role for proline synthesis and transport in Listeria monocytogenes barotolerance

To assess the contribution of proline biosynthesis to listerial barotolerance. Using a Listeria monocytogenes proBA deletion mutant, incapable of synthesizing proline, together with a proline-overproducing strain, the contribution of proline synthesis to listerial barotolerance was determined. The ΔproBA strain does not survive as well as the wild type when subjected to treatment of 500 MPa in rich media and 400 MPa in minimal media (c. 1 log lower survival in both conditions). Betaine and carnitine decrease the ability of the wild type to survive at low pressures (300 MPa), but confer normal or slightly increased levels of protection at higher pressures (350 and 400 MPa). A functional proline synthesis system is required for optimal survival of Listeria following treatment at high-pressure (HP) levels (500 MPa in brain heart infusion and 400 MPa in defined medium), particularly where other compatible solutes are absent or limiting. Given the potential of HP processing as an effective food processing/safety strategy, understanding how pathogens such as Listeria have evolved to cope with such stresses is an important food safety consideration. In this context, the work presented here may help to develop safer and more effective processing regimens.

High Pressure Inactivation of HAV Within Mussels

The potential of high pressure processing to inactivate hepatitis A virus (HAV) within Mediterranean mussels (Mytilus galloprovincialis) and blue mussels (Mytilus edulis) was evaluated. HAV was bioaccumulated within mussels to approximately 6-log10 PFU by exposure of mussels to HAV-contaminated seawater. After shucking, 5 min pressure treatments of 300, 325, 350, 375, and 400 MegaPascals (MPa) were performed at room temperature (18–22°C). For blue mussels, log10 PFU reductions of HAV averaged 2.1 and 3.6 for treatments of 350 and 400 MPa, while for Mediterranean mussels reductions of 1.7 and 2.9 log10 PFU MPa were observed for equivalent treatments. These results demonstrate that high pressure processing is capable of inactivating HAV within mussels.

Inactivation of a calicivirus and enterovirus in shellfish by high pressure

Abstract This study demonstrates the potential of high pressure (HP) processing to reduce viral contamination in shellfish. Bovine enterovirus, which is structurally similar to hepatitis A virus, was more pressure-resistant than feline calicivirus, a surrogate for norovirus. Both viruses were more pressure-resistant when treated in “naturally” contaminated mussels and oysters, compared to seawater and culture medium, suggesting that the medium can have a significant protective effect against HP treatment. Treatment at pressures of 250 MPa showed only a limited inactivation of either virus in shellfish, suggesting that relatively mild HP treatments (approximately 260 MPa) currently used for the commercial processing of oysters, principally to assist the shucking process, may be insufficient to ensure the safety of shellfish for human consumption, particularly in relation to human pathogenic viruses. Industrial relevance High pressure (HP) processing is increasingly being used in the commercial processing of oysters, principally to assist the opening or shucking of oysters. Little is known about the effect of HP treatment on pathogens in shellfish, particularly human enteric viruses, which are the predominant cause of shellfish-borne disease. This article demonstrates the inactivation of surrogate animal viruses, as potential models for noroviruses and hepatitis A virus, by HP processing and compares the efficacy of inactivation when viruses are treated in culture medium, seawater and shellfish. The potential of HP processing to reduce viral contamination in shellfish is discussed in light of these findings.