Effect of thermosonication on peroxidase,pectin methylesterase activities and on bioactive compounds in custard apple juice

Custard apple juice faces long term storage challenges such as pink discoloration and bitterness due to peroxidase activity. Therefore, inactivation of peroxidase becomes a necessity for longer shelf life of custard apple and its application in food preparations. Heat processing has certain pitfalls such as loss in nutritional contents of custard apple juice, thereby adversely affecting the sensory quality. In the present study, thermosonication of custard apple juice at a constant temperature of 30?±?1?°C (20 kHz, 67.84 W/cm²) from 0 to 40 min has been studied with respect to peroxidase and pectin methylesterase inactivation. Effect of thermosonication has also been studied on bioactive components such as total phenolics and flavonoids along with enzyme inactivation. Complete inactivation of peroxidase and pectin methylesterase with 0% residual activity was achieved within 40 min and 50 s, respectively. Total phenolics were found to increase from 70.9?±?1.6 to 81.7?±?2.5 mg GAE/g. Sonication was found to have no significant effect (P?>?0.05) on pH, °Brix, titratable acidity. Ascorbic acid content remained relatively unaffected during sonication. Hence, thermosonication may be employed as food processing technique where retention of bioactive components have been achieved along with safety and quality attributes.     

Thermosonication of peach juice: investigation of PPO and POD activities,physicochemical and bioactive compounds changes,and development of FT-IR–based chemometric models for the evaluation of quality

In this research, the effect of thermosonication on peach juice was investigated. Enzyme inactivation increased with increasing power, temperature, and time. Enzymes were completely inactivated by thermosonication at 60 °C that was lower than the complete inactivation temperature (70 °C) of thermal treatment. Generally, as pH decreased, titratable acidity and °Brix increased by increasing temperature for each thermosonication treatment. The color of peach juice was preserved, and it became lighter. The bioactive components were protected with thermosonication. Fourier transform infrared (FT-IR) spectroscopy with chemometrics was used to evaluate polyphenol oxidase and peroxidase activity and quality attributes during thermosonication treatment. Moreover, the treatment methods were differentiated using principal component analysis, and models that correlated enzyme activity, quality attributes, and bioactive compounds with infrared spectra were constructed using partial least-squares. FT-IR with chemometrics can be used as a reliable method in peach juice quality determination during thermosonication.     

Antioxidant activities of onion (Allium cepa L.) peel extracts produced by ethanol,hot water,and subcritical water extraction

Onion (Allium cepa L.) peels were extracted by ethanol, hot water and subcritical water (SW) extraction and their antioxidant activities were evaluated. Extraction yields of SW extraction were 4-fold higher than ethanol extraction. However, the ethanol extraction increased the total phenolics contents (327.5 mg GAE/g extract) and flavonoids contents (183.95 mg QE/g extract) in the onion peel extract. The onion peel extracts by ethanol extraction showed greater DPPH radical scavenging activities and greater antioxidant activities determined by ferric thiocyanate assay than those by hot water extraction and SW extraction at 165°C. Antioxidant activity of onion peel extract by SW extraction at 110°C was similar to that of ethanol extraction. HPLC profiles revealed that SW extraction at lower temperature (110°C) increased the concentration of quercetin. These results demonstrated that the onion peel extracts produced by SW extraction technique have great potential as a source for useful antioxidant.     

Effect of thermosonication on quality improvement of tomato juice

Inactivation of pectinmethylesterase (PME) and polygalacturonase (PG) is required to minimize quality loss in tomato products. Tomato juice was subjected to thermosonication (TS) (24 kHz), at amplitudes of 25, 50 and 75 μm at 60, 65 and 70 °C or heat only treatments. The TS treatment at 60 °C, 65 °C and 70 °C for 41.8, 11.7 and 4.3 min exposure, respectively reduced PME activity by 90%. The heat only treatment at 60 °C, 65 °C and 70 °C for 90.1, 23.5 and 3.5 min, respectively inactivated PME by 90%. TS treatments with 25–75 μm amplitude had no significant impact on the inactivation efficiency between 60 and 70 °C. After TS the average particle size decreased noticeably (< 30 μm) and viscosity increased 2–4 fold, compared to the heat treated or untreated juice (180 μm)_. These results suggest that TS at 60 and 65 °C could be useful to obtain tomato juice with a low residual PME activity and high viscosity.Industrial relevanceThe processed tomato industry is constantly in search for potential alternative processes to conventional “cold break” and “hot break” treatments that could inactivate the pectic enzymes of importance. The findings of this study would help the industry to inactivate pectinmethylesterase (PME) enzyme at a lower temperature range and also achieve a higher viscosity due to the mechanical effects of thermosonication. Low temperature treatment would enable the retention of fresh-like properties of tomato juice. Based on the findings of this study, thermosonication could be considered as a potential alternative to conventional “cold break” and “hot break” treatments of tomato juice.     

Optimisation of pressurised liquid extraction for antioxidative polyphenolic compound from Momordica charantia using response surface methodology

Pressurised liquid extraction (PLE) of antioxidant compounds from bitter gourd fruits (Momordica charantia) in aqueous ethanolic solvent was investigated using response surface methodology at laboratory scale to understand key impact of extraction variables. Extraction efficiency was optimised by measuring the yield of extraction, total phenolic content (TPC), total flavonoid content (TFC), ferric reducing/antioxidant power assay (FRAP) and radical scavenging activity (RSA). The optimal extraction conditions were reached at 80% ethanol concentration, 10‐min extraction time and at 160 °C. Under these extraction conditions, values of TPC (5.40 ± 0.30 g GAE per 100 g), TFC (1.50 ± 0.10 g QE per 100 g), FRAP (778.55 ± 10 μmol eq Fe (II) g^?1), yield (178.50 ± 5.50 mg g^?1 dc) and RSA (75.50 ± 4.50%) were achieved. Furthermore, statistical analysis revealed that antioxidative attributes of bitter gourd extract were strongly and positively correlated with extraction temperature and ethanol concentration rather than processing time. This study illustrated that PLE has the potential to extract antioxidant compounds from tropical fruit vegetables in an accelerated manner. Furthermore, influential parameters affecting the process could be optimised for further industrial intake.     

Extraction of polyphenols and antioxidants from pomegranate peel using ultrasound: influence of temperature,frequency and operation mode

The objective of this research was to investigate the effects of temperature (40–70 °C), frequency (37 and 80 kHz) and ultrasonic operation mode (normal, pulse and sweep), and their interactions on the recovery of phenolic compounds and antioxidants present in pomegranate peel using ultrasound-assisted extraction. The content of individual phenolic compounds, total phenolic compounds (TPC), antioxidant capacity (AC) and total extract yield (X₀) were analysed. Significant effects were observed between some sources of variation in recovery of individual compounds at TPC and X₀, and no significant effect was observed for AC. The process and conditions studied shown to be interesting to extract antioxidants, since a high antioxidant capacity was verified in the extracts. Temperatures around 50–60 °C, using 37 kHz frequency, and normal or pulse modes were the conditions that provided better yields of phenolic compounds and X₀. Regarding AC, the best condition observed was at 70 °C, 80 kHz frequency and continuous mode.     

Antioxidant activity and β-glucan contents of hydrothermal extracts from maitake (Grifola frondosa)

Maitake (Grifola frondosa) was hydrothermally extracted at 4 different temperatures (121, 130, 140, and 150°C) for 30 and 60 min, and the total phenolic content (TPC), antioxidant activity, and β-glucan content of the extracts was evaluated. The highest TPC was detected in the extract at 150°C treated for 60 min with 13.61 mg gallic acid equivalents (GAE)/g. The antioxidant activity of the maitake extracts, evaluated by determining DPPH radical scavenging activity (RSA), ABTS RSA, reducing power, and tyrosinase inhibitory activity increased with increasing treatment temperature and time. The content of β-glucan was the highest (5.13%) in the extract prepared at 140°C for 30min. These results suggest that hydrothermal extraction could be used as a tool to increase the antioxidant activity of maitake extracts.     

Sequential high pressure extractions applied to recover piceatannol and scirpusin B from passion fruit bagasse

Passion fruit seeds are currently discarded on the pulp processing but are known for their high piceatannol and scirpusin B contents. Using pressurized liquid extraction (PLE), these highly valuable phenolic compounds were efficiently extracted from defatted passion fruit bagasse (DPFB). PLE was performed using mixtures of ethanol and water (50 to 100% ethanol, w/w) as solvent, temperatures from 50 to 70 °C and pressure at 10 MPa. The extraction methods were compared in terms of the global yield, total phenolic content (TPC), piceatannol content and the antioxidant capacity of the extracts. The DPFB extracts were also compared with those from non-defatted passion fruit bagasse (nDPFB). Identification and quantification of piceatannol were performed using UHPLC–MS/MS. The results showed that high TPC and piceatannol content were achieved for the extracts obtained from DPFB through PLE at 70 °C and using 50 and 75% ethanol as the solvent. The best PLE conditions for TPC (70 °C, 75% ethanol) resulted in 55.237 mg GAE/g dried and defatted bagasse, whereas PLE at 70 °C and 50% ethanol achieved 18.590 mg of piceatannol/g dried and defatted bagasse, and such yields were significantly higher than those obtained using conventional extraction techniques. The antioxidant capacity assays showed high correlation with the TPC (r > 0.886) and piceatannol (r > 0.772). The passion fruit bagasse has therefore proved to be a rich source of piceatannol and PLE showed high efficiency to recover phenolic compounds from defatted passion fruit bagasse.     

Antihypertensive properties of aqueous extracts of vegetable leaf‐fortified bread after oral administration to spontaneously hypertensive rats

This study investigated the potential cardiovascular health benefits of leavened bread produced from wheat flour that contained 1%, 2% and 3% additions of leafy vegetable powders obtained from Amaranthus viridis (AO), Solanum macrocarpon (SM) or Telfairia occidentalis (TO). Dried breads were extracted with water at 60 °C followed by analysis for total polyphenolic content (TPC), as well as in vitro inhibitions of angiotensin‐converting enzyme and renin activities. HPLC analysis of the bread extracts indicated the presence of mainly rutin, gallic acid, myricetin and caffeic acid. TPC of the vegetable‐fortified breads was significantly (P < 0.05) higher (5.8–7.6 mg gallic acid equivalent, GAE/g) than that of control bread (5.5 mg GAE/g). Oral administration of 100 mg dried extract/kg body weight to spontaneously hypertensive rats led to reductions (up to 42 mmHg) in systolic, diastolic and mean arterial blood pressure in comparison with 20 mmHg for the control bread.     

Multi-frequency power thermosonication treatments of clear strawberry juice: Impact on color,bioactive compounds,flavor volatiles,microbial and polyphenol oxidase inactivation

Strawberry juice is popular among consumers for its bright color, unique flavor and rich nutrition. The aim of this study was to explore the suitable multi-frequency power thermosonication (TS) treatments to meet the requirements of microbiological safety for strawberry juice while maximizing the preservation of its quality properties. The TS treatments included 60 °C /5 min and 55 °C /15 min under dual-frequency concentrated ultrasound (DCU) and 60 °C /15 min and 55 °C /20 min under sweep-frequency divergent ultrasound (SDU). The results showed that all treatments could meet the requirements of commercial sterility (at 90 °C for 1 min). Compared with thermal processing (TP) at 90 °C for 1 min, TS treatment significantly improved the color properties of strawberry juice. SDU-60 °C and SDU-55 °C greatly retained the active ingredients in the strawberry juice. TS treatments had a stronger ability to maintain the aroma compared to TP. Especially, SDU-60 °C was the best treatment at retaining quality properties of strawberry juice with the highest comprehensive sensory evaluation score (7.68). Therefore, the results can provide scientific basis for industrial production of strawberry juice.Industrial relevanceIn the current study, results showed that TS maximized the overall quality of strawberry juice while achieving the effect of sterilization and enzyme inactivation. Among them, SDU-60 °C was the best treatment method to maintain the quality characteristics of strawberry juice, which can effectively reduce the loss of approximately 70% of total phenolic content. Thus, it provides the theoretical basis and technical support for the industrial production of strawberry juice.     

Antioxidant activity of 4 cultivars of persimmon fruit

In this study, the antioxidant activity of persimmon fruit of 4 different persimmon cultivars cultured at Korea was evaluated. There were 3 astringent persimmon cultivars [‘Bongok’ (BO), Japanese Hatchiya; ‘Cheongdobansi’ (CB); and ‘Dogeunjosaeng’ (DJ), Japanese Tonewase] a 1 non-astringent persimmon cultivar [‘Seochonjosaeng’ (SJ), Japanese Nishimurawase] fruits. After preparing extracts of fruits according to parts (calyx, pulp, and peel) with 4 different solvents (acetone, ethanol, methanol, and water), total phenolic contents (TPC) and antioxidant activity were determined. The extracts of calyx showed significantly higher TPC and antioxidant properties than those of the other persimmon parts. The highest 1,1-diphenyl-2-picrylhydrazyl (DPPH) radical scavenging activity (IC₅₀=43.36±1.78 μg/mL) and reducing power (IC₅₀=81.93±1.18 μg/mL) were found at acetone extract of SJ calyx, while SJ pulp extracts showed relatively lower antioxidant activities. Astringent persimmons showed relatively higher antioxidant activity than non-astringent persimmons in peel and pulp parts. These results indicated that persimmons have different antioxidant activity depending on cultivars and parts.     

Quality of Freeze Concentrated Orange Juice

Pasteurized Valencia and Temple orange juices concentrated to 45°Brix by freeze concentration retained their fresh juice flavor. Direct steam infusion heating to inactivate enzymes allowed more rapid heating than indirect heating and successfully lowered juice peel oil during vacuum cooling. Except for considerable pulp reduction of feedstream juices, there were few differences from normal citrus juice recovery procedures for freeze concentration. Since the product retained most of the aroma constituents of fresh juice, careful handling and high quality feed juice prior to freeze concentration was much more important than for evaporation. Fresh juice freeze concentrated to 45°B, then pasteurized at temperatures of 80°, 97° and 111°C had reduced sucrose (up to 25%) as the temperature increased to 111°C.     

Spray-Drying of Antioxidant-Rich Blueberry Waste Extracts; Interplay Between Waste Pretreatments and Spray-Drying Process

This study aimed to establish an efficient route for converting blueberry waste material (BWM) into antioxidant-rich powders. Extracts were produced from BWM by an aqueous method using water acidified with citric acid, in the absence or presence of Pectinex Ultra SP-L and Cellubrix. All BWM extracts contained antioxidants including phenolic acids, anthocyanins, and flavonoids (total phenolic content (TPC) 3655–4369 mg gallic acid equivalent (GAE) and total anthocyanin content (TAC) 219–296 mg cyanidin-3-glucoside equivalents (CyGE) per 100 g dry extract). Extractions at 50 °C yielded higher TPC and TAC but lower vitamin C and pectin contents than extractions at 20 °C. Spray-drying BWM extracts produced at 50 °C (no enzymatic treatments) and an encapsulant (alginate or inulin) at an inlet temperature 150 °C and feed temperature 50 °C yielded powders with desired dark purplish blue color, water activity (0.25–0.33), flowability, reconstitution time (23–46 s in water or milk), TPC (25–30 mg GAE/g), TAC (17–20 mg CyGE/g), storage stability, and Bifidobacterium-boosting properties. Enzymatic pretreatments of BWM did not confer any advantages in preserving antioxidants in powder products, suggesting that some intrinsic BWM components (e.g., pectins) may play an important role in the encapsulating process. The use of alginate as the encapsulant/drying aid afforded higher powder yields, superior protection of antioxidants, better stability over a prolonged storage or elevated temperature storage, greater retention of TPC/TAC under simulated gastrointestinal conditions, and greater Bifidobacterium-boosting effects, compared to powders prepared using inulin. Thus, simple aqueous extraction methods and spray-drying technology hold enormous promise for producing antioxidant-rich powders from blueberry processing by-products or waste.     

Antioxidant Activity of Loquat (Eriobotrya japonica Lindl.) Fruit Peel and Pulp Extracts in Stabilization of Soybean Oil During Storage Conditions

The antioxidation activities of Eriobotrya japonica (Lindl.) fruit peel and pulp extracts were determined using DPPH, β-carotene, and Rancimat methods. Results showed that ethanol-water extract of peel and ethanol extract of pulp had the highest antioxidant activity. Protective effects of extracts in stabilization of soybean oil were tested and compared to tert-butyl hydroquinone by measuring peroxide values, free fatty acids, thiobarbituric acid, oxidative stability, and conjugated dienes and trienes values during storage (65 days at 25°C). Results showed that the ethanol-water extract of peel at 400 ppm exhibited stronger antioxidant activity, but the highest effect was observed in tert-butyl hydroquinone.     

Pasteurization of carrot juice by combining UV-C and mild heat: Impact on shelf-life and quality compared to conventional thermal treatment

The combination of UV-C radiation and mild heat (UV-H) treatment is a promising strategy for synergistically increasing microbial inactivation in low UV-transmitting juices. In this research, we explored the suitability of UV-H treatment in carrot juice pasteurization and its impact on juice quality during shelf-life compared to that of thermal pasteurization. UV-H treatment at 60 °C (3.92 J/mL, 3.6 min) enabled reductions of over 5 log₁₀ cycles in the reference pathogens and a significant reduction in spoilage yeasts, bacteria, and bacterial spores. The activity of pectin methylesterase and polyphenol oxidase was reduced by UV-H treatment to levels close to those of low-temperature pasteurization (60 °C/18.1 min). The native population of total aerobic bacteria, lactic acid bacteria, and yeasts and molds of UV-H-treated juice remained undetectable during 29 days of cold storage. Furthermore, viscosity, cloud stability, and the color of fresh juice were better preserved by UV-H treatment than by thermal pasteurization throughout storage.Industrial relevanceThis study demonstrates that UV-H treatment is a beneficial alternative to conventional thermal processing in carrot juice pasteurization, since appropriate inactivation levels of pathogenic and spoilage microorganisms can be reached while better preserving the quality attributes of fresh juice throughout its shelf-life.     

Quality comparison of carrot juices processed by high-pressure processing and high-temperature short-time processing

The effects of high-pressure processing (HPP) at 550 MPa for 6 min and of high-temperature short-time (HTST) processing at 110 °C for 8.6 s on carrot juice were evaluated. After HPP and HTST, the total plate count (TPC) was found to significantly decrease by 4.30 and 4.88 log₁₀ CFU/mL, respectively, and yeasts and molds (Y&M) were completely inactive. HPP-treated juice showed higher carotenoids, polyphenols, antioxidant capacity, viscosity, turbidity, and lower browning degrees (BDs) than HTST-treated juice, while HTST-treated juice contained higher polyacetylenes. HPP provided a more fresh-like quality and exhibited better aroma, taste, and overall acceptability. During 20 days of storage at 4 °C, both HPP- and HTST-treated juices were microbiologically safe (i.e., TPC < 2.4 log₁₀ CFU/mL, and Y&M were not detected), and their antioxidant capacities decreased linearly due to a decrease in carotenoid and polyphenol contents. The two juices did not precipitate any solids when their particle sizes decreased, and their viscosity increased; however, their organoleptic properties deteriorated as storage time increased.Industrial RelevanceThis study was intended to develop fresher and more stable carrot juice, which is not available on the market now. Acid blanching for a proper time was proved as an effective process in preventing juice serum isolation phenomenon of HPP juice, which is more likely to be accepted by consumers. HPP-treated juice had an advantage in nutritional and organoleptic properties than HTST-treated juice. This study provided a comprehensive technical support for novel application of HPP in carrot juice processing.     

Optimization of Enzymatic Hydrolysis Pretreatment Conditions for Enhanced Juice Recovery from Guava Fruit Using Response Surface Methodology

The effect of enzyme concentration (0.16–0.84 mg/100 g guava pulp), incubation temperature (36.6–53.4 °C), and incubation time (0.95–11 h) on juice yield was studied. A central composite rotatable design was used to establish the optimum conditions for enzymatic hydrolysis of guava to obtain maximum juice yield. Significant regression model describing the changes of juice yield with respect to hydrolysis parameters were established with the coefficient of determination, R ² = 0.85. Enzyme concentration was the most significant variable affecting the juice yield. The recommended enzymatic treatment condition from the study was at the enzyme concentration 0.70 mg/100 g guava pulp, incubation time 7.27 h, and incubation temperature 43.3 °C.     

Comparison of UV-C and thermal treatments for the preservation of carrot juice

The aim of the present study was to investigate the effectiveness of UV-C and thermal treatments on the shelf life of carrot juice. Carrot juice samples were exposed to UV-C radiation and thermal treatment. After the treatments, all carrot juice samples were stored at 4 °C for 16 days. Parameters taken into account were: physicochemical [colour values (L*, a*, and b*) and browning index, viscosity, optical density, density, pH, turbidity], microbiological [total plate count mesophilic, total plate count psychrotrophic, lactic acid bacteria Enterobacteriaceae and yeast and moulds) and sensory attributes. Results showed that the shelf life of carrot juice samples was 4 days for the fresh (control samples) and increased to 12 days for the thermally and UV-Ctreated, respectively. In addition, no significant changes occurred in the investigated physicochemical parameters, while sensory characteristics were not downgraded by UV-C treatment. Present results obtained, support the use of UV-C technology for improving shelf life stability of carrot juice.     

Application of Green Technology for the Acquisition of Extracts of Araçá (Psidium grandifolium Mart. ex DC.) Using Supercritical CO2 and Pressurized Ethanol: Characterization and Analysis of Activity

Brazil is home to a wide variety of flora, including several lesser known species, such as araçá that were processed in this study using two green technologies consecutively: supercritical fluid extraction (SFE) for nonpolar fraction and pressurized liquid extraction. For polar fraction, the experiments followed a central composite design involving ethanol as solvent, with temperature and static time in each bath as independent variables. Both extracts were analyzed for antioxidant and antimicrobial activities. Total phenolics content (TPC) was determined for all ethanol extracts. In the araçá essential oil (AEO) obtained by SFE, the extraction yield was 2.33%. The three major compounds of AEO were α‐pinene (20.75%), p‐cymene (20.50%), and o‐cymene (20.05%). In ethanol extracts, the high yield (14.49%) was obtained at 74 °C/6 min and the major TPC (136.95 mg GAE/100 g) at 60 °C/9 min. Ethanol extracts presented good antioxidant activity (EC₅₀ = 6.37 mg/mL) at 74 °C/6 min. AEO was unable to reduce DPPH? concentration by 50%. Both extract types presented an inhibitory effect against Staphylococcus aureus, Pseudomonas aeruginosa, and Bacillus cereus, while only the ethanol extracts presented effect against Listeria monocytogenes. This work had the aim to present the innovation of the use of a whole typical Brazilian fruit that gives rise to extracts with excellent properties for employment in both the pharmaceutical and food industries.     

Inactivation of Oxidative Enzymes by High-Intensity Pulsed Electric Field for Retention of Color in Carrot Juice

The effects of high-intensity pulsed electric fields (HIPEF) on oxidative enzymes and color of fresh carrot juice were studied. A response surface methodology (RSM) was used to evaluate the effect of pulse polarity (mono or bipolar mode), pulse width (from 1 to 7 μs), and pulse frequency (from 50 to 250 Hz) on color and peroxidase (POD) inactivation of carrot juice treated by HIPEF. The total treatment time and the electric field strength were set at 1,000 μs and 35 kV/cm, respectively, at a temperature below 35°C. The physicochemical characteristics of carrot juice were measured. There was a linear relationship between electrical conductivity and temperature of the carrot juice. The results showed that HIPEF-treated carrot juice at 35 kV/cm for 1,000 μs applying 6 μs pulse width at 200 Hz in bipolar mode led to 73.0% inactivation of POD. The color coordinates did not change significantly. Therefore, HIPEF was effective in POD inactivation and carrot juice color preservation.