Isoflavone profile of a high intensity pulsed electric field or thermally treated fruit juice-soymilk beverage stored under refrigeration

A fruit juice-soymilk (FJ-SM) beverage was treated by high intensity pulsed electric fields (HIPEF) (35 kV/cm with 4 μs bipolar pulses at 200 Hz for 800 or 1400 μs) or heated (90 °C, 60 s) in order to evaluate and compare the effects of both technologies on the isoflavone profile along the storage at 4 °C. Total isoflavone content was determined by quantification of aglycone and glucoside forms analyzed with HPLC. Immediately after treatments, all the evaluated samples showed a higher concentration of glucosides than aglycones, genistin being the most abundant glucoside. Heat treated samples showed higher initial concentration of glucosidic forms as compared to the untreated or HIPEF treated beverages. No significant changes were observed in total isoflavone content after the increasing HIPEF treatment time from 800 to 1400 μs. During the storage, genistein, daidzein and daidzin content increased; while genistin showed a slight decrease, irrespective of the treatment applied. In this way, total isoflavone content tend to increase throughout the time in all the evaluated samples. After 56 days of storage, there was no significant difference in HIPEF treated and fresh FJ-SM beverages, the latter being slightly higher in those thermally treated. As a result, HIPEF could be a good technology in order to obtain FJ-SM beverages with a high content of isoflavones and fresh-like characteristics. Considering the great concentration of isoflavones in untreated and treated FJ-SM beverages, their consumption could be a good way to increase the isoflavone daily intake of the population.Industrial relevanceHIPEF processing could be a competent technology in order to obtain FJ-SM beverages with fresh-like appearance and similar isoflavone content than just made products. The fruit juice-soymilk beverage evaluated in the present research has a great isoflavone content regarding to commercial soy based beverages. Its consumption could increase the current isoflavone intake of the population. Industry could apply this non-thermal technology in order to meet current consumers' claims for quality foods with high nutritional values.     

Effect of processing and food matrix on calcium and phosphorous bioavailability from milk-based fruit beverages in Caco-2 cells

Calcium and phosphorus bioavailability from different milk-based (whole milk, skimmed milk and soya milk) fruit beverages as affected by thermal treatment (TT) and high-pressure processing (HPP) was determined by means of the paired in vitro gastrointestinal digestion (solubility method)/Caco-2 cell model. Ca bioaccessibility was significantly higher in HPP (98.4% ± 1.6%) versus TT (91.3% ± 1.9%), but Ca bioavailability was equal in all different matrixes independently of the processing treatment used. HPP samples improved P bioaccessibility (98.7% ± 2.5% versus 87.3% ± 2.2%) and P bioavailability by Caco-2 cells versus TT samples—soya milk- and whole milk-based beverages being the samples with the highest bioavailability values (56.8% ± 1.3% and 40.1% ± 9.9% versus 15.0% ± 2.1% and 16.8% ± 2.8%, respectively). Therefore, HPP improves Ca and P bioaccessibility, and P bioavailability versus TT samples, and can be used as an alternative to TT in the manufacture of functional foods with improved nutritional value and health benefits.     

Phenolic compounds,microstructure and viscosity of onion and apple products subjected to in vitro gastrointestinal digestion

Microstructure, viscosity and their relationship with bioaccessibility of phenolic compounds in onion and apple products (untreated and HPP) and commercial quercetin supplement throughout a dynamic gastrointestinal digestion (GID) model were investigated. In non-digested (ND) samples, untreated and HPP-onion presented higher total phenolic and flavonol content (TFC-HPLC and TPC-FC) than apple counterparts. TFC-HPLC decreased throughout GID phases in all samples studied. TFC-HPLC bioaccessibility was higher in onion (~17.6%) than in apple (~10%) and in quercetin supplement (0.027%). HPP did not improve TFC-HPLC bioaccessibility. Throughout GID, onion and apple showed a significant decrease in both consistency (K) and apparent viscosity at 10 s⁻¹ but higher values were found in apple. These data agree with TFC-HPLC and TPC-FC decrease and with the lower bioaccessibilities of apple compared with onion. Food matrix had a more significant effect than HPP on TFC-HPLC bioaccessibility, which is related to the rheological behavior of the GID-phases.Industrial relevanceHigh-pressure processing (HPP) (400 MPa at 25 °C during 5 min) combined with freeze-drying enhanced significantly flavonols extractability (TFC-HPLC) in onion and apple and in some cases their bioaccessibility. Bioaccessibility of bioactive compounds in each food matrix is being required by industrials and consumers concerned to know the actual amount of bioactive compounds that are available for intestinal absorption. The change of the matrices viscosity studied throughout in vitro gastrointestinal digestion (GID) could predict the bioaccessibility of these bioactive compounds. HPP could be proposed as a strategy for increasing the extractability of bioactive compounds in vegetable derived products.     

Soymilk phenolic compounds,isoflavones and antioxidant activity as affected by in vitro gastrointestinal digestion

The aim of this research was to evaluate changes in the phenolic compounds, isoflavones and antioxidant activity of soymilk following in vitro gastrointestinal digestion (including dialysis). Gastric digestion significantly influenced the release of bioactive substances from the soymilk matrix, increasing the concentration of total phenolic components (35% as the sum of individuals and 14% by Folin–Ciocalteu [F–C] method), total isoflavone content (22%) and total antioxidant activity (76%). The concentration of all those compounds was reduced significantly in the duodenal fraction in comparison to gastric digestion and their lowest concentration was observed in the dialysed fraction, where phenolic acids were not detected. The bioaccessibility of soymilk phenolic compounds was 15% as the sum of individuals and 20% by F–C assay; isoflavones 36% and constituents with antioxidant activity 27%. Results suggest that most of these compounds were sufficiently available to be absorbed and could contribute health benefits.     

Impact of high intensity pulsed electric field on antioxidant properties and quality parameters of a fruit juice-soymilk beverage in chilled storage

The effects of high-intensity pulsed electric fields (HIPEF) treatment (35 kV/cm, 4 μs bipolar pulses at 200 Hz for 800 or 1400 μs) on the microbial stability, quality parameters and antioxidant properties of a fruit juice-soymilk (FJ-SM) beverage along the storage time at 4 °C were compared to those obtained by thermal pasteurization (90 °C, 60 s). HIPEF processing for 800 μs ensured the microbial stability of the beverage during 31 days; however, longer microbial shelf-life (56 days) was achieved by increasing the treatment time to 1400 μs or by applying a thermal treatment. Peroxidase and lipoxygenase of HIPEF treated beverages were inactivated by 17.5-29% and 34-39%, respectively; whereas thermal treatment achieved 100% and 51%. During the storage, vitamin C content and antioxidant capacity depleted with time, and they were higher in FJ-SM beverages processed by HIPEF than in those thermally treated. Instead, total phenolic content of beverages did not present significant changes over the time, and it was higher in the 1400 μs-HIPEF treated beverages. In general, color, soluble solids, pH, and acidity values were not significantly affected by the processing treatments. Beverage viscosity increased over time, regardless of the treatment applied. Hence, application of HIPEF may be a good alternative treatment to thermal processing in order to ensure microbiological stability, high nutritional values and fresh-like characteristics of FJ-SM beverages.     

Changes on phenolic and carotenoid composition of high intensity pulsed electric field and thermally treated fruit juice–soymilk beverages during refrigerated storage

The effects of high intensity pulsed electric fields (HIPEF) (35 kV/cm with 4 μs bipolar pulses at 200 Hz for 800 or 1400 μs) or thermal (90 °C, 60 s) treatments over phenolic and carotenoid compounds of a fruit juice–soymilk (FJ–SM) beverage stored at 4 °C were evaluated and compared, having the untreated beverage as a reference. Coumaric acid, narirutin and hesperidin were the most abundant phenolic compounds in the FJ–SM beverage, while the main carotenoids were lutein, zeaxanthin and β-carotene. Immediately after HIPEF or heat processing, hesperidin content of the beverage showed a huge rise, resulting in a significant increase on the total phenolic concentration. Regarding carotenoid concentration, HIPEF or thermal treatment lead to a significant decrease; lutein, zeaxanthin and β-cryptoxanthin being the most affected compounds. In contrast, the content of some individual phenolics and carotenoids increased with time, while others tended to decrease or remained with no significant changes with regards to their initial values. Total phenolic concentration seemed to be highly stable during storage; while, total carotenoid content gradually diminished, irrespectively of the treatment applied. Overall, the changes observed in HIPEF treated FJ–SM beverage were less than those in the heat processed one. Hence, HIPEF is a feasible technology to obtain FJ–SM beverages with extended shelf-life and a similar profile of antioxidant compounds to freshly made beverages.     

Physical and structural changes in liquid whole egg treated with high-intensity pulsed electric fields

Liquid whole egg (LWE) is currently pasteurized through the application of heat; however, this treatment entails deleterious effects against some of the functional and technological properties of the product. In this study, the effect of high-intensity pulsed electric fields (HIPEF) processing (field strength: 19, 32, and 37 kV/cm) was compared to the traditional heat pasteurization (66 °C for 4.5 min). Different physical and structural characteristics of LWE, subjected or not to homogenization, were evaluated and compared, having the untreated LWE as a reference. Thermal treatment caused an increase in the viscosity of LWE, especially in nonhomogenized samples. HIPEF treatments did not modify the original color of LWE, whereas thermally treated samples developed an opaque appearance. LWE treated at 19 and 32 kV/cm exhibited a similar foaming capacity as fresh untreated egg, whereas thermal processing and PEF treatments of 37 kV/cm caused a substantial decrease in the foaming capacity of untreated liquid egg. Regarding the microstructure, the lipoprotein matrix appeared to be less affected by the HIPEF than by heat treatment if compared to the control. In addition, heat pasteurization had a significant impact on both the water-soluble protein content of the LWE samples (19.5% to 23.6% decrease) and the mechanical properties of the egg gels (up to 21.3% and 14.5% increase in hardness and cohesiveness, respectively). On the other hand, these parameters were not substantially affected in the HIPEF-treated samples. Heat-induced gels obtained from HIPEF-treated samples did not exhibit remarkable differences in the water-holding capacity (WHC) with respect to heat-pasteurized samples. PRACTICAL APPLICATION: The impact of high-intensity pulsed electric fields (HIPEF) processing on technological properties of liquid-whole egg was investigated and compared to that of thermal processing. Heat treatments cause a severe impact on the foaming capacity, the water-soluble protein content, and the rheological properties of liquid egg samples, whereas HIPEF treatments better preserved the food matrix structure. Microscopic observations support these results, thus suggesting that HIPEF-processing has potential application for the preservation of liquid egg through nonthermal means.     

Effects of Thermal and High-pressure Treatments on the Microbiological,Nutritional and Sensory Quality of a Multi-fruit Smoothie

Fruit juices have become an important product for the healthy food world. In the last 5 years, the sales of industrial juices treated by non-thermal preservation technologies such as high-pressure processing (HPP) have strongly increased. In the present study, the effect of the application of two stabilization treatments, mild heating (MH; 80 °C for 7 min) and high-pressure processing (HPP; 350 MPa for 5 min), on multi-fruit smoothies was compared on a wide range of quality parameters immediately after treatment and during a refrigerated storage of 21 days. From the physico-chemical and instrumental colour point of view, immediately after treatment, HPP smoothies were more similar to the fresh product than those treated by MH. During storage, the colour of MH smoothies was more stable although HPP ones showed lower browning index and viscosity more similar to the untreated product. Additionally, HPP provided smoothies with better sensory properties and higher nutritional quality than MH. In general, HPP smoothies were more similar to the untreated product. However, HPP smoothies kept a residual enzyme activity which is likely to limit the shelf life of this multi-fruit smoothie.     

Volatile compounds and changes in flavour‐related enzymes during cold storage of high‐intensity pulsed electric field‐ and heat‐processed tomato juices

BACKGROUND: The effects of high‐intensity pulsed electric field (HIPEF) processing (35 kV cm^?1 for 1500 µs, using 4 µs bipolar pulses at 100 Hz) on the production of volatile compounds and flavour‐related enzymes in tomato juice were investigated and compared with those of thermal processing (90 °C for 30 or 60 s). RESULTS: Tomato juice treated by HIPEF showed lower residual lipoxygenase (LOX) activity (70.2%) than juice heated at 90 °C for 60 s (80.1%) or 30 s (93.2%). In contrast, hydroperoxide lyase (HPL) was almost completely inactivated when the juice was subjected to 90 °C for 60 s, whereas roughly 50% of the control tomato juice was depleted after HIPEF treatment or thermal processing at 90 °C for 30 s. A slight decrease was observed in the initial LOX activity of treated and untreated samples during storage, whereas initial HPL activity was strongly affected over time. CONCLUSION: HIPEF‐treated juice exhibited higher levels of compounds contributing to tomato aroma than untreated and heat‐treated juices throughout storage. Thus HIPEF processing can preserve flavour quality and stability of tomato juice compared with conventional thermal treatments. Copyright © 2010 Society of Chemical Industry     

Novel approaches in improving the quality and safety aspects of processed meat products through high pressure processing technology - A review

BackgroundIn recent years, there has been growing consumer demand for the minimally processed and chemical additives free Ready-To-Eat (RTE) healthier meat products. On the other hand processed and RTE meat products have been notified as the primary cause for food borne outbreaks in different countries that commonly associated with emerging pathogens such as Salmonella, Listeria monocytogenes and Escherichia coli species.Scope and approachHigh pressure processing (HPP) has been renewed as a best non-thermal intervention for extending the shelf-life and safety of RTE meat products without altering the sensory and nutritional properties. Meat products are complex medium with different physical and chemical compositions that influence the lethality of the microorganisms during HPP. Using high pressure levels (above 600 MPa) for complete sterility of meat products may not be economically feasible more over it may negatively affect the product quality characteristics. The present review aimed to explore the recent research investigations addressed the multi hurdle approaches to increase the effectiveness of HPP at lower processing levels in order to reduce the processing costs and to improve the safety and quality of processed meat products.Key findings and conclusionsThe combination of natural antimicrobials (plant bioactive compounds and bacteriocins) and antioxidants (plant phenolic compounds) as additional hurdles through different mechanisms (active and intelligent packaging) during HPP can definitely be an effective and innovative intervention in ensuring the complete safety of processed meat products. Moreover, the development of low salt meat products with optimum quality attributes can be highly possible through HPP technology.     

Influence of high-intensity pulsed electric field processing parameters on antioxidant compounds of broccoli juice

The effect of high-intensity pulsed electric field (HIPEF) processing parameters (electric field strength, treatment time, and polarity) on broccoli juice carotenoids, vitamin C, total phenolic (TP) content and antioxidant capacity (AC) was evaluated. Results obtained from HIPEF-processed broccoli juice were compared with those of thermally treated (90 °C/60 s) and untreated juices. HIPEF processing parameters influenced the relative content (RC) of bioactive compounds, and the relative AC (RAC). Maximum RC of lutein (121.2%), β-carotene (130.5%), TP (96.1%), vitamin C (90.1%) and RAC (5.9%) was reached between 25 and 35 kV/cm and from 2000 μs to 500 μs. The highest RAC and RC of bioactive compounds were observed in HIPEF treatments applied in bipolar mode, except for vitamin C. HIPEF-treated broccoli juice exhibited greater RC of bioactive compounds and RAC than juice treated by heat. HIPEF technology could be considered a promising option for preserving the antioxidant quality of broccoli juice.Industrial relevanceVegetable juices are becoming more and more popular because of their wide range of health-related compounds. Particularly, broccoli juice is attracting the food industry attention because it contains high amounts of vitamins, carotenoids and phenolic compounds, among other bioactive compounds. Broccoli juice requires treatment conditions that protect its microbial, nutritional and sensorial quality. HIPEF is a non-thermal technology for liquid food preservation that inactivates microorganisms and enzymes without compromising the nutritional and sensorial features of foods. Consequently, this technology could be used in the food industry as an alternative for thermal treatment to preserve the bioactive compounds present in vegetable juices, offering to consumers a healthy product.     

High pressure processing pretreatment of Chinese mitten crab (Eriocheir sinensis) for quality attributes assessment

The present study evaluated high pressure processing (HPP) pretreatment effects on the quality attributes of Chinese mitten crab (Eriocheir sinensis). Process parameters were optimized (300 MPa for 5 min) and the effects of HPP pretreatment on the total edible part of Eriocheir sinensis were investigated. The results showed that steamed loss has no significant difference and water holding capacity of inner meat was increased by approximately 51.33% with HPP pretreatment. HPP pretreatment can also decrease hardness value of crab carapace and preserve texture properties of crab leg meat. Compared with raw inner meat, results of DSC analysis of inner meat with HPP pretreatment has revealed that the denaturation temperature and the enthalpy of protein were decreased remarkably. The results of water distribution indicated that HPP pretreatment reduced the loss of entrapped water in inner meat. Finally, compare with the conventional steamed crabs, it has been detected that the aroma of the edible viscera of crabs has a significant difference with HPP pretreatment. Above findings indicated that HPP pretreatment retains quality attributes of Eriocheir sinensis well, in the meantime improves the processing efficiency since steaming time can be reduced by applying HPP pretreatment.Industrial relevanceHPP is a novel non-thermal technique widely used in the field of food production. Compared with conventional thermal processing, it is important for assessing the impact of HPP pretreatment on the quality attributes of crab in order to obtain high-quality products. According to recent studies, HPP pretreatment has been confirmed to be able to improve the quality of hot processed crabs. By applying 300 MPa for 5 min on Eriocheir sinensis, the total edible part was improved, and the water holding capacity of crab inner flesh was increased. Moreover, HPP pretreatment can also decrease hardness value of crab carapace and preserve sensorial properties of crab leg meat. These results indicated HPP pretreatment retains high quality characteristics of Eriocheir sinensis and reduces steaming time by which means the processing efficiency can be improved. This work provided further support for the use of HPP in Eriocheir sinensis.     

Comparative study on color,viscosity and related enzymes of tomato juice treated by high-intensity pulsed electric fields or heat

The effects of high intensity pulsed electric fields (HIPEF) processing (35 kV/cm for 1,500 μs using bipolar 4-μs pulses at 100 Hz) on color parameters and viscosity, as well as peroxidase (POD), pectin methylesterase (PME) and polygalacturonase (PG), were evaluated during 77 days of storage at 4 °C and compared to thermal treatments at 90 °C for 1 min or 30 s for unprocessed tomato juice. HIPEF-treated tomato juice showed higher values of lightness than the thermally processed and the untreated juice throughout storage time (P < 0.05). Viscosity of HIPEF-treated tomato juice was also greater than both thermally treated and untreated for the first 35 days of storage. POD of HIPEF-treated tomato juice was inactivated by 97% whereas in the case of the thermally treated, 90 and 79% inactivation was achieved after 1 min and 30 s, respectively. The highest PME inactivation in tomato juice was obtained by PEF (82%) and heat treatment at 90 °C for 1 min (96%). PG of PEF-treated tomato juice was inactivated by 12% whereas thermal treatments at 90 °C for 1 min or 30 s achieved 44 and 22%, respectively. Despite the low rates of PG inactivation obtained, the pattern followed in the residual activity along the storage time was similar in the tomato juice treated by HIPEF than the thermally processed.     

Evaluation of the economic and environmental sustainability of high pressure processing of foods

A comparative evaluation of the environmental/economic performance of High Pressure Processing (HPP) technology for food processing is made using Life Cycle Costing (LCC) and Life Cycle Assessment (LCA) methodologies. Thermal pasteurization (TP), in the form of indirect system (with energy recovery) and of retort process, and modified atmosphere packaging (MAP), are taken as benchmark during the evaluation, as traditional food processing technologies typically used to process orange juice (TP) and sliced Parma ham (MAP). Primary data on costs and consumption of HPP, TP and MAP plants were obtained from companies. Secondary data for LCA analysis was retrieved from the Ecoinvent 3.4 database and from available scientific literature.As a result of the assessment, HPP appears as more expensive than both TP processes, but turns out to have a lower environmental impact in almost all impact categories. Compared to MAP, HPP is less expensive and also has a lower impact in most of the impact categories, as MAP requires a significant amount of packaging materials and food gases. Industrial relevance: High pressure processing (HPP) is a well-known non-thermal technology, which since its introduction has had limited use, mainly due to the high cost of the electricity required for the process. Nowadays, however, new technologies in the food processing and new food product applications could make it more widely used. To correctly evaluate whether HPP technology is actually cost-effective and has low impact on the environment, detailed economic and environmental analyses have been carried out in this paper. Results are expected to enhance the use of HPP technology in industry.     

Comparing the Impact of High-Pressure Processing and Thermal Processing on Quality of “Hayward” and “Jintao” Kiwifruit Purée: Untargeted Headspace Fingerprinting and Targeted Approaches

This study evaluated process-induced quality changes in kiwifruit purée of two commercial cultivars (green kiwifruit, “Hayward”, and gold kiwifruit, “Jintao”) treated by equivalent microbial safety-based processing: high-pressure processing (HPP; 600 MPa/3 min) and thermal processing (TP; P ^{85 °C} _{8.3 °C} = 5min). This comparative study was performed using both targeted, analyzing a priori selected quality attributes (color, sugars, organic acids, and vitamin C) and untargeted headspace-solid phase microextraction-gas chromatography-mass spectrometry approaches, combining multivariate data analysis techniques (partial least squares discriminant analysis and variable identification). HPP provided a better retention of color and vitamin C compared to TP. Sugar and organic acid were less affected by HPP and TP. Methyl and butyl esters were detected at higher amounts in both processed purée, compared to untreated purée. For processed samples, furanones, terpenes, and alcohols were detected at higher amounts after TP and aldehydes were detected at higher amount after HPP. Overall, the quality of HP-treated samples is clearly closer to that of fresh samples compared to thermally treated samples and HP treatment avoids the formation of typical temperature-induced compounds.     

Effects of High-Intensity Pulsed Electric Fields Processing Parameters on the Chlorophyll Content and Its Degradation Compounds in Broccoli Juice

The influence of high-intensity pulsed electric fields (HIPEF) parameters including electric field strength (15–35 kV/cm), treatment time (500–2,000 μs), and polarity (monopolar or bipolar mode) on the content of chlorophylls (Chls), pheophytin (Phe), chlorophyllide (Chlide), and pheophorbide (Phb) and chlorophyllase activity (Chlase) in broccoli juice were assessed. A significant effect of HIPEF parameters on Chlase, Chls, and Chls degradation compounds was observed through a response surface methodology design. However, polarity did not exert influence neither on Chl a nor on Chl b. The optimum HIPEF treatment was found to be 35 kV/cm for 1,980 μs in bipolar mode, where the highest content of Chls was kept, the lowest Chlase residual activity was reached, and the minimal quantities of Chls degradation compounds content were formed. Additionally, at these HIPEF conditions, broccoli juice exhibited greater content of Chls than thermally treated or untreated juice. These outcomes demonstrated that HIPEF processing could be a suitable technology to maintain the Chls content in broccoli juice.     

Isoflavone Profile in Soymilk as Affected by Soybean Variety,Grinding, and Heat‐Processing Methods

Isoflavones impart health benefits and their overall content and profile in foods are greatly influenced at each step during processing. In this study, 2 soybean varieties (Prosoy and black soybean) were processed with 3 different grinding (ambient, cold, and hot grinding) and heating methods (traditional stove cooking, 1‐phase UHT, and 2‐phase UHT) for soymilk making. The results showed after cold, ambient, and hot grinding, the total isoflavones were 3917, 5013, and 5949 nmol/g for Prosoy; the total isoflavones were 4073, 3966, and 4284 nmol/g for black soybean. Grinding could significantly increase isoflavone extraction. The grinding process had a destructive effect on isoflavones and this effect varied with grinding temperature. Different heating methods had different effects on different isoflavone forms. Two soybean varieties showed distinct patterns with respect to the change of isoflavone profile during processing.     

Physicochemical and in vitro digestion properties of soy isoflavones loaded whey protein nanoparticles using a pH-driven method

Soy isoflavones are widely used as a dietary supplement. However, the bioavailability of soy isoflavones is low due to the poor water solubility. Whey protein is an excellent biopolymer to encapsulate functional ingredients. In this study, soy isoflavones loaded whey protein nanoparticles were prepared using a pH-driven method. The physicochemical properties and in vitro digestion properties of the nanoparticles were investigated. The results showed that the physicochemical properties of nanoparticles were regulated by the mass ratios of soy isoflavones to whey proteins. Hydrogen bonding and hydrophobic interactions were confirmed in generating soy isoflavones loaded nanoparticles, which modified the thermal stability and secondary structure of whey proteins. The nanoparticles could pass through simulated gastric digestion to deliver soy isoflavones into the intestinal tract, responsible for the increased digestion stability and bioaccessibility of soy isoflavones. Moreover, the controlled release of soy isoflavones from nanoparticles can be achieved with a mechanism of non-Fickian diffusion. This study may provide useful information about the utilization of soy isoflavones loaded whey protein nanoparticles to develop functional foods.     

The effect of high pressure processing on nutritional value and quality attributes of Cucumis melo L.

To determine the effect of cultivar on high pressure processing (HPP) performance three commercial melon varieties were assessed before and after HPP for vitamin C and β-carotene by HPLC and for ferric ion reducing capacity (FIRC) using the Ferric Reducing Ability of Plasma (FRAP) assay. Total titrable acids (TTA), °Brix and colour were also recorded for fresh,−HPP (material cut and packaged) and +HPP samples (material cut, packaged and subject to HPP). The HP process was non-thermal so as to determine the effect of pressure alone on these phytochemicals. There were significant differences between cultivars in vitamin C, β-carotene, TTA, °Brix and colour parameters in fresh samples prior to HPP. HPP did not have an effect on TTA or °Brix, but colour was adversely affected. FIRC and vitamin C concentrations were decreased by HPP and these losses were cultivar dependent for vitamin C. Levels of β-carotene were significantly increased. Cultivar was identified as an important parameter in raw material selection for HPP and retention of vitamin C as a good measure of both quality and cultivar suitability.Industrial relevanceThere is an increasing consumer demand for fresh, natural and healthy fruit and vegetable products with an extended shelf life. This demand is driving industry to look at alternative preservation technologies. HPP has the potential to deliver safe, preserved fruit and vegetables through enzyme inactivation of microbe destruction. HPP removes the need for additives or preservatives and the process is therefore viewed as closer to “natural” by consumers. We show that HPP results in minimal loss of sensorial properties and health-promoting phytochemicals; thus providing consumers a high quality, healthy product with extended shelf life. The introduction of non-thermal processing techniques has the potential to move the focus of the Australian food processing industry from safety to the dual aims of safety and health, resulting in an increase of health-promoting phytochemicals in highly consumed processed foods.