High Pressure Processing Techniques Research Articles

High‐pressure processing for inactivation of enzymes, microbes, and its effect on nutritional composition of tender coconut water

AbstractTender coconut water (TCW) processing has been a challenge and is often accompanied by challenges such as beneficial bioactive compound deterioration and enzymatic and non‐enzymatic browning initiation. Fresh TCW was treated with a combination of pressure (350–550 MPa) and treatment time (3–7 min). This study unveiled the potency of high‐pressure processing (HPP) in reducing undesirable enzyme activity, such as polyphenol oxidase (PPO) and peroxidase (POD) activity in TCW by up to 36.472% and 30.606%, respectively. The maximum loss of vitamin C was reported to be 7.84% at 550 MPa/7 min compared to the untreated one, which is very acceptable in terms of quality retention. The total phenolic content and antioxidant activities were well retained and increased in the HPP‐treated TCW samples. Similarly, the total and reducing sugar reduction was within 20%–25%. The findings of this investigation demonstrated the effectiveness of high‐pressure processing in preserving quality and reducing the activity of enzymes that cause deterioration in TCW. Moreover, the aerobic plate count (APC) and yeast and mold count (YM) were decreased significantly (p < 0.05) after 450 MPa/5 min treatment.Practical applicationsOver the years, the food industry has been facing a consistent challenge in perishable product processing (juices, milk, meat, etc.) to extend its shelf‐life while keeping its nutritional and sensory properties intact. This study presented a significant insight into TCW processing regarding enzyme, microbial inactivation, and nutritional property preservation using HPP technology. Moreover, from a quality perspective, this work enables the HPP‐treated TCW to be as close to a fresh one without any preservative addition. HPP technique is believed to appeal to industries that seek a green alternative technique to thermal processing (which makes processed foods unacceptable among consumers) to produce minimally treated foods on a commercial scale.

Effect of Salt (Sodium Chloride) Replacement With Potassium Chloride, High Pressure Processing, and Cold Storage at 4°C on Beef Sausage Volatile Compounds.

This study aimed to investigate the partial substitution of 0, 25 and 50% sodium chloride (NaCl) by potassium chloride (KCl) coupled with high-pressure processing (HPP) effects on volatile compounds and lipid oxidation of beef sausage at five (0, 3, 7, 14, and 21) different cold storage days (4°C). The odor activity values (OAV) of the various compounds were visualized by heat map analysis. Thiobarbituric acid reactive substances (TBARS) of the samples treated with 100% NaCl and HPP increased by an average of 0.52 ± 0.01 mg MDA/kg compared with the control (100% NaCl-no HPP) across the 21 storage days. In addition, 50% NaCl substitution with KCl in combinations with HPP treatments increased TBARS across the 21 storage days by an average of 0.40 ± 0.02 mg MDA/kg compared with no HPP treatment. However, on day 3, there was a sharp decrease in TBARS by an average of 0.10 ± 0.01 mg MDA/kg compared with days 0, 7, 14, and 21 in all treatments. At the end of 21 days of storage, a total of 227 volatile compounds were identified and quantified in the beef sausage, including 43 aldehydes, 46 phenols, 8 ketones, 30 alcohols, 14 acids, 12 esters, 27 terpenes, and 47 alkanes. However, no ketone compounds were detected on days 7, 14 and 21; esters on day 14 and acids on days 14 and 21 in the samples treated with or without HPP across the salts levels. However, high OAVs (OAV > 1) were obtained after partial substitution of NaCl with KCl at 25 and 50% with HPP treatment compared to the samples not treated with HPP. The aroma perceived in the beef sausage was due to compounds with the highest OAVs such as; pentadecanal, benzyl carbazate, anethole, myristicin, o-cresol, phenylacetaldehyde and (E)-methyl isoeugenol, pentadecanal, hexanoic acid, octanoic acid, eugenol, trans-2-nonenal, trans-2-octenal, trans-2-decenal, 2-butyl-1-octanol, 2,3-butanedione, ethyl hexanoate, ethyl octanoate, (-)-4-terpineol which had an OAV > 1 as compared to the other compounds with an OAV < 1. In conclusion, 25 and 50% NaCl partial replacement with KCl coupled with HPP technique can be considered in producing low-NaCl beef sausage in order to improve the flavor and decrease lipid oxidation during cold storage.

The Impact of Processing Methods on the Quality of Honey: A Review

The quality of honey are naturally differs depending on its geographical origin and the botanical source of honeydew collected by the bees. These characteristics influence the physical appearance of honey such as its colour lightness and liquid thickness; which then may influence the honey attractiveness to the consumers. The thickness of honey is correlate with its moisture content. The higher the moisture content of honey, the higher the risk of fermentation, thus honey is commonly process before marketed. However, the processing methods may change the nutritional content, original taste and physical characteristics of the honey. This paper reviews the effect of five types of processing methods on the quality of honey; which are the spray-drying process, thermal treatment technique, thermosonication technique, high-pressure processing technique and microwave processing method. Overall, it can be concluded that all processing methods reviewed in this article altered the nutritional quality and physicochemical characteristics of honey. However, the different processing methods may alter the quality of honey differently. This information is very important for consumer to understand the reasons on the variability of honey quality in the market. It also will help the honey industry players to choose the best method in processing their honey and ensuring the best quality of honey can be produce to fulfil the consumers need and satisfaction.

Viability of sous vide, microwave and high pressure processing techniques on quality changes during shelf life of fresh cowpea puree.

An innovative cowpea puree containing 78.8% of fresh cowpea seeds was developed. Microwave treatment (8 kW/35 s), high hydrostatic pressure (550 MPa/10 min/23 ℃) or sous vide treatment (80 ℃, 3 min) were assayed as processing techniques. Blended fresh cowpea samples were used as control. Quality changes during 21 days at 5 ℃ were studied. Sous vide samples showed a relevant loss during storage of viscoelastic parameters, like elastic modulus (G') and viscous modulus (G″), which was also perceived in the sensory evaluation. On the contrary, high hydrostatic pressure and microwave treatments were able to preserve consistency, texture and taste. However, physicochemical properties, mainly colour, were greatly influenced by thermal treatments, although high hydrostatic pressure treatment preserved greenness. Total phenolic content and total antioxidant capacity were more affected by high hydrostatic pressure than by microwave treatments. In conclusion, microwave and high hydrostatic pressure processing treatments seem to be quite interesting techniques to develop legume-based products.

N-type Ba0.3Ni0.15Co3.85Sb12 skutterudite: High pressure processing technique and thermoelectric properties

In this letter, Ni substitution for Co and Ba filling into the voids were simultaneously applied to the CoSb3 bulks by the high pressure and high temperature (HPHT) method. As the results, the polycrystalline Ba0.3Ni0.15Co3.85Sb12 skutterudite bulks were successfully synthesized and the systematic thermoelectric properties were investigated. In our experiments, the synthesized time was sharply shortened to 30 min, which is markedly an advantage for mass production. The multiple textures and microstructures were revealed, including vortices-like structures, defects, and lattice dislocations. Remarkably, pressure tuning led to the increase of the Seebeck coefficient and electrical resistivity, yielding an optimized power factor of 11.7 × 10−4 Wm−1K−2 in the Ba0.3Ni0.15Co3.85Sb12 sample prepared at 3 GPa at room temperature, which yielded a 10-fold improvement in power factor and showed distinct reduction of thermal conductivity compared with pure CoSb3 sample. The maximum zT value 0.91 was obtained at 700 K for Ba0.3Ni0.15Co3.85Sb12 sample. The experimental results suggest that the effective elements doping combining with HPHT synthesis could optimize electrical and thermal transport properties in skutterudites.

Effects of High-pressure Processing Technique on the Quality and Shelf Life of Chinese Style Sausages

Fresh Chinese-style sausage is a traditional product in Taiwan. Because it is made from fresh meat, the initial total plate count of packed products can be lowered using non-thermal preservation methods. The high pressure processing (HPP) technique (100-1000 MPa) can be applied to sterilize packed products to reduce microbial contamination. This study applied the HPP technique to fresh Chinese-style sausages and evaluated their physicochemical, microbial and sensory characteristics. The results revealed that when the sausages are processed at a pressure greater than 400 MPa, the a value of color increases. Regarding the texture properties, the hardness, cohesiveness, gumminess and chewiness decreases as the pressure rises. Moreover, an increased pressure effectively reduces the initial total plate count. The sensory analysis showed that after HPP, the sausages exhibit significantly high acceptability in texture and overall characteristics. In addition, in a storage treatments conducted at 7 °C, a control group reached 6 log CFU/g in total plate count and swelling was observed after 80 days of treatment. however, sausages that received HPP (at 600 MPa for 10 min) exhibited a significantly lower total plate count of 3 log CFU / g after 90 days of treatment. These results indicate that HPP considerably reduces the initial plate count of the sausages as well as suppresses the growth of the total plate count during the storage period. Therefore, HPP can extend the shelf life of fresh Chinese-style sausages by at least 30%.

High pressure processing controls microbial growth and minimally alters the levels of health promoting compounds in grapefruit (Citrus paradisi Macfad) juice

Abstract Grapefruit juice treated with high pressure processing (HPP), thermal processing (TP) and control (no treatment) was analyzed for the levels of various bioactive compounds and color, during 21 days of storage at 4 °C. The TP treatment juice had significantly ( P ≤ 0.05) higher L * and b * values than HPP and control juice throughout the storage period. A gradual decline in the level of ascorbic acid was noticed in all the treatments with significantly lower levels in TP treatment as compared to control and HPP during 0 and 7 days of storage analysis. The HPP treatment had no significant ( P ≤ 0.05) effect on the levels of citric acid, flavonoids, limonoids and coumarins, in comparison to the control treatment. The levels of carotenoids were significantly ( P ≤ 0.05) lower among both processing treatments and control at 21 days after storage as compared to the levels present at the initial 0 day after storage. No microbial growth was noticed in both the treatments and control at 28 days after storage. Industrial relevance High pressure processing is an innovative non-thermal processing technique which is applicable for industrial processing of fruit juices. However, its effect on health promoting bioactive compounds present in grapefruit has not been studied. The present study focused on evaluating the effect of HPP and TP techniques on the levels of bioactive compounds and shelf life. Results from this study suggest that HPP treatment maintains the levels of bioactive compounds, color and controls microbial growth as compared to the control treatment. Thus, HPP technique could be applied for providing fresh like grapefruit juice without altering the levels of health beneficial bioactive compounds to consumers.

Assessment of Clostridium perfringens Spore Response to High Hydrostatic Pressure and Heat with Nisin

The elimination of spores from low-acid foods presents food-processing and food-safety challenges to high-pressure processing (HPP) developers as bacterial spores are extremely resistant to pressure. Therefore, the effects of pressure (400-800 MPa), temperature (35-95 °C), and nisin (0-496 IU/mL) on the inactivation of Clostridium perfringens AS 64701 spores at various pressure-holding times (7.5-17.5 min) were explored. A second-order polynomal equation for HPP- and nisin-induced inactivation of C. perfringens spores was constructed with response surface methodology. Experiment results showed that the experimental values were shown to be significantly in agreement with the predicted values because the adjusted determination coefficient (R (Adj)²) was 0.9708 and the level of significance was P < 0.0001. The optimum process parameters (obtained by solving the quadratic polynomal equation) for a six-log cycle reduction of C. perfringens AS 64701 spores were pressure of 654 Mpa, temperature of 74 °C, pressure-holding time of 13.6 min, and nisin concentration of 328 IU/mL. The validation of the model equation for predicting the optimum response values was verified effectively by ten test points that were not used in the establishment of the model. Compared with conventional HPP techniques, the main process advantages of HPP-nisin combination sterilization in the UHT milk are, lower pressure, temperature, natural preservative (nisin), and in a shorter treatment time. The synergistic inactivation of bacteria by HPP-nisin combination is a promising and natural method to increase the efficiency and safety of high-pressure pasteurization.

Inactivation of Bacillus coagulans Spores Subjected to Combinations of High-Pressure Processing and Nisin

In this study, the influence of pressure (300 to 700 MPa), mild heat (15°C to 75°C), and nisin concentration (0 to 200 IU mL-1) on the survival of Bacillus coagulans AS 1.2009 spores in milk buffer at different processing times (7.5 to 17.5 min) was investigated. Response surface methodology (RSM) was employed, and a quadratic equation for high-pressure processing (HPP) and nisin-induced inactivation was developed using RSM. By analyzing the response surface and the corresponding contour plots, as well as solving the quadratic equation, the experimental values were significantly in agreement with predicted values; the adjusted coefficient of determination (RAdj2) was 0.9588, and the level of significance was p < 0.0001. The optimum process parameters for a 6-log cycle reduction of B. coagulans AS 1.2009 spores were pressure of 550.0 MPa, temperature of 41°C, pressure-holding time of 12.2 min, and nisin concentration of 120 IU mL-1. The adequacy of the model equation for predicting the optimum response values was validated effectively for ten test points. Compared to conventional HPP techniques, the main process advantages of combined HPP-nisin treatment in milk buffer are reduced requirements for pressure, temperature, and use of a natural preservative (nisin), with a shorter treatment time.

High pressure processing of fruits and vegetables

Purpose of review: Hi gh pressure processing (HPP) is one of the many novel techniques for processing food materials. This revi ew details potential applications of the HPP technique for fruit and vegetable processing. Recent findings: HPP employs high pressures (400–1200 MPa) to kill microorganisms and inactivate the enzymes that cause un desirable changes in fruits and vegetables, which reduces their shelf-life. This technique can be applied with minimal increase in product temperature. HPP is gaining in popularity because of its potential to achieve desirable effects with minimum changes i n sensory and nutritional attributes, and reliable food safety. Directions for future research: Fu ture research should: evaluate synergistic effects among pressure, temperature and other v ariables, investigate the influence of pressure on reduction/eli mination of pathogenic and spoilage microbial populations, invest igate the inactivation of enzymes in fruits and vegetables using a proper experimental design so that kinetic parameters are q uantified, identify and evaluate the critical pr ocess factors for the survival of pathogens or surrogates in a statistical manner, and de velop Hazard Analysis and Critical Control Point plans for the application of HPP for the processing fruits and vegetabl es.