The effects of conventional thermal, microwave heating, and thermosonication treatments on the quality of sugarcane juice

Application of thermosonication for guava juice processing: Impacts on bioactive, microbial, enzymatic and quality attributes

The present work explores different conditions of thermosonication (TS) processing that would ensure microbiological and enzymatic safety for guava juice while simultaneously maximizing the preservation of its quality attributes. The guava juice was subjected to TS treatment (frequency: 40 kHz; power: 200 W; Temperature: 40, 60, and 80 °C; Time: 2, 6 and 10 min) and was compared with fresh and pasteurized (90 °C/60 s) juice samples. The objectives of the research work were to determine the effect of thermosonication on the quality attributes such as total soluble solids (TSS), pH, titratable acidity, cloud value, color attributes, total phenolic contents, total flavonoid contents, antioxidant activity, ascorbic acid levels, enzymatic, microbiological, and sensory properties. The thermosonicated and pasteurized samples showed no significant (p > 0.05) changes in pH, total soluble solids, and titratable acidity. TS improved the cloud value and color attributes. Furthermore, TS enhanced total phenols (10 to17%), flavonoids (5 to 25%), antioxidant activity (10.45% to 14.55%) and retention of ascorbic acid (61.98-83.32%) relative to control. Thermosonicated sample at 80 °C/10 min gives the maximum inactivation of Pectin methyl esterase (PME), Peroxidase (POD) and Polyphenol oxidase (PPO) enzymes. While both thermosonication and pasteurization drastically decreased the microbial count to undetectable levels, only TS exhibited modest improvement in sensory qualities. The results demonstrated that TS can enhance the overall safety, quality, and commercial viability of guava juice as a practical substitute to pasteurization.

Synergistic effect of microwave heating and thermosonication on the physicochemical and nutritional quality of muskmelon and sugarcane juice blend

Melons (Cucumis melo L.) are highly popular due to its delicate and delightful flavor in the worldwide. However, the flavor of the melon juice was easily affected by thermal treatments and unpleasant cooking smell during production process. Sugarcane (Saccharum officinarum) juice is a proven nutritious beverage with high levels of antioxidants, polyphenols, and other beneficial nutrients. Due to its low sugar content, combined with sugarcane, muskmelon-sugarcane blend juice gives an appealing and exotic drink. The research was planned to evaluate the effect of thermo-sonication (20 kHz, 70% amplitude, 5, 10 and 15 min) and microwave (90 °C, 400 W, 120 sec) on physicochemical parameters including pH, titratable acidity, total soluble solids (TSS), total phenolic contents (TPC), total flavonoid contents (TFC) and antioxidant capacity of muskmelon and sugarcane juice blend, during storage of 90 days at refrigeration (4±1 °C). The statistical results showed that synergism of sonication and microwave treatments had a significant (p ≤ 0.05) influence on pH, TSS, titratable acidity, TPC, TFC and antioxidant capacity. T₃ (15 min of sonication and 120 s of microwave) showed the maximum TSS (12.00±0.40 °B), pH (5.07±0.02), TPC (484.33±10.41 mg GAE/100 mL), TFC (261.73±11.32 mg CE/100 mL), and antioxidant activity (381.62±17.72 µg AAE/100 mL), as compared to untreated samples. Thermosonication for 15 min caused maximum retention of TPC, TFC and antioxidant capacity of blend juice during 90 days of storage, whereas in untreated samples these parameters were found highly decreased during storage. Thus, sonication and microwave can be recommended as an alternative to both conventional pasteurization processes and chemical preservatives.

Processing of verjuice by ultrasound-assisted microwave heating: An assessment on the enzyme activity retention, technological parameters, and bioactive properties

The present study evaluated the effect of ultrasonication prior to microwave heating applied at 60 °C, 70 °C, and 80 °C on the quality characteristics of verjuice. The sole microwave heating and conventional heating were also performed at the same temperature levels, and effectiveness of three different treatments were evaluated. The required treatment times were decided based on obtaining <10% pectin methylesterase (PME) activity, and ultrasound pretreatment provided the least heating durations. Turbidity, browning index, and viscosity values increased by 3.4 to 14.8-fold, 0.24 to 1.26-fold, and 9.2% to 48.0%, respectively, after all thermal treatments, while Brix values decreased by 1.4% to 15.7%. Ultrasound pretreatment revealed relatively lower browning index in all temperature levels, and almost the highest viscosity values were obtained in sonication pretreated microwave heating as compared with sole microwave and conventional heating. The minimum turbidity value (0.035) was determined in ultrasound-assisted microwave heating at 60 °C. The highest antioxidant capacity (DPPH and ABTS) values were achieved by ultrasound-assisted microwave heating (up to 4.96 and 28.4 mmol Trolox equivalent (TE)/kg, respectively) followed by microwave heating (up to 4.30 and 27.0 mmol TE/kg) and conventional heating (up to 3.72 and 26.8 mmol TE/kg). Furthermore, ultrasonication resulted in better retentions of PME residual activity during 60 days of refrigerated storage (4 °C). Ultrasound pretreatment prior to microwave heating could be a convenient approach for juice processing by reducing the required treatment time and by conserving the quality parameters.

Comparison of interaction, structure, and cell proliferation of α-lactalbumin-safflower yellow complex induced by microwave heating or conventional heating

BACKGROUND

The protein-polyphenol interaction mechanism has always been a research hotspot, but their interaction is affected by heat treatment, which is widely applied in food processing. Moreover, the effects of microwave or water-bath heating on the protein-polyphenol interaction mechanism have been not clarified. The pasteurization condition (65 °C, 30 min) was selected to compare the effects of microwave or water bath on binding behavior, structure, and cell proliferation between α-lactalbumin (α-LA) and safflower yellow (SY), thus providing a guide for the selection of functional dairy processing conditions.

RESULTS

Microwave heat treatment of α-LA-SY resulted in stronger fluorescence quenching than that of conventional heat treatment. Moreover, the binding constant K_a of all α-LA-SY samples was augmented significantly after microwave or water bath treatment, and microwave-heated α-LA-SY showed the maximum K_a . Fourier transform infrared spectroscopy showed that microwave heating resulted in more ordered structures of α-LA into its disordered structures than water bath heating. However, the ferric reducing antioxidant power and chroma value of α-LA-SY were more reduced by microwave heating than by water bath heating. Moreover, microwave heating facilitated the cell proliferation of α-LA-SY compared with water bath treatment.

CONCLUSION

It was demonstrated that microwave heating promoted interaction between α-LA and SY more than water bath heating did. Microwave heat treatment was a safe and effective way to enhance the binding affinity of α-LA to SY, being a potential application in food industry. © 2022 Society of Chemical Industry.

Pomegranate Peel Powder: In Vitro Efficacy and Application to Contaminated Liquid Foods

In this study the recycling of pomegranate peel powder (PPP) was proposed. In particular, the use of powder loaded in a silk fibroin polymeric matrix to create an active pad was tested. For the sake of comparison, the powder alone was also analysed. Both powder and active pad efficacy was assessed in two different food systems, soymilk (rich in proteins), preliminarily contaminated with Pseudomonas spp. and yeasts, and apple juice (rich in carbohydrates), preliminarily contaminated with Alyciclobacillus acidoterrestris. Three different concentrations of powder alone and powder in the pad were tested (5%, 7.5% and 10% w/v) in both types of beverages. To assess a possible dependence of the efficacy on the powder granulometry, different powder sizes were preliminarily analysed on Pseudomonas spp. and yeasts using an in vitro test. PPP was effective on both Pseudomonas spp. and yeasts. No significant differences appeared among the tested granulometries and therefore in the subsequent tests powder with an average diameter of 250 µm was used. Results recorded with soymilk and apple juice were different. When applied to the soymilk, the activity of PPP in the pad was less effective than that recorded when the powder was directly added to the beverage. With the two highest powder concentrations directly added to food, more than four log cycle reductions in Pseudomonas spp. and yeast cells were recorded, compared to soymilk without any powder. Compared to the control sample, all the soymilk samples either with PPP or with the active pad showed a delayed microbial and fungal growth. When applied to apple juice, both powder and pad were effective at completely inhibiting the proliferation of A. acidoterrestris (<102 CFU/g).

Potential impact of ultrasound, pulsed electric field, high-pressure processing and microfludization against thermal treatments preservation regarding sugarcane juice (Saccharum officinarum)

Sugarcane juice (Saccharum officinarum) is a proven nutritious beverage with high levels of antioxidants, polyphenols, and other beneficial nutrients. It has recently gained consumer interest due to its high nutritional profile and alkaline nature. Still, high polyphenolic and sugar content start the fermentation in juice, resulting in dark coloration. Lately, some novel techniques have been introduced to extend shelf life and improve the nutritional value of sugarcane juice. The introduction of such processing technologies is beneficial over conventional processes and essential for producing chemical-free, high-quality, fresh juices. The synergistic impact of these novel technologies is also advantageous for preserving sugarcane juice. In literature, novel thermal, non-thermal and hurdle technologies have been executed to preserve sugarcane juice. These technologies include high hydrostatic pressure (HHP), ultrasound (US), pulsed electric field (PEF), ultraviolet irradiation (UV), ohmic heating (OH), microwave (MW), microfludization and ozone treatment. This review manifests the impact of novel thermal, non-thermal, and synergistic technologies on sugarcane juice processing and preservation characteristics. Non-thermal techniques have been successfully proved effective and showed better results than novel thermal treatments. Because they reduced microbial load and retained nutritional content, while thermal treatments degraded nutrients and flavor of sugarcane juice. Among non-thermal treatments, HHP is the most efficient technique for the preservation of sugarcane juice while OH is preferable in thermal techniques due to less nutritional loss.

Key Drivers for Non-Centrifugal Sugar Cane Research, Technological Development, and Market Linkage: A Technological Roadmap Approach for Colombia

Food science innovation depends on consumers' needs and is currently seeking functional food with health effects. Non-centrifugal cane sugar (NCS) is known for its potential health effects, but there is a lack of holistic analysis on technological advancement and socio-economic and market trends for decision-making in the development of the technology. The aim of this article was to analyse the research trends, recent patents, and market trends and niches for NCS to structure an NCS technological roadmap. Scientometric, bibliometric methods, and global and local market information on NCS were used. Comprehensive analysis of the worldwide research trends and patents on NCS processing and of the growth of the main niche markets for Colombian NCS exports in the last five years was conducted. Finally, with the information obtained, an NCS technological roadmap was structured, which can be used as a tool for planning innovation processes and supporting the development of new research using market information and new norms forged by the COVID-19 pandemic for Colombian case. Furthermore, the methodological design could be used for other NCS producer countries.

SUPPLEMENTARY INFORMATION

The online version contains supplementary material available at 10.1007/s12355-022-01200-9.

Research progress in fluid and semifluid microwave heating technology in food processing

Microwave is a form of electromagnetic radiation that has high penetration and heating efficiency in food processing. Uneven heating is the main problem of microwave processing, especially in solid foods. Fluid and semifluid media, which are good carriers in microwave processing, have uniform dielectric properties and good material fluidity. Herein, we review the development, application prospects, and limitations of microwave in fluid and semifluid food processing and the research progress in microwave heating with steam as carrier. The mixture of generated steam and tiny micro droplets from food material under the action of microwave can absorb microwave and transfer heat evenly, which effectively improves the uniformity of microwave heating. Due to the relatively uniform dielectric properties and consistent texture of fluid and semifluid food materials, uneven heating phenomenon during their microwave processing can be significantly inhibited. Based on the development of microwave heating technology and equipment design, the microbial inactivation and enzyme inhibition in fluid and semifluid food were improved and food product with better retention of nutrients and sensory profile were produced. Also, microwave radiation can be used to prepare the printing material or process the printed product for 3D food printing, which enhances the added value of 3D printed products and the personalization of food manufacturing. In future research, intelligent control technology can be applied in the microwave processing of fluid and semifluid food materials for various applications. Therefore, the processing conditions can be adjusted automatically.

Quality Evaluation of Lemon Cordial Stored at Different Times with Microwave Heating (Pasteurization)

Consumer interest in food quality and safety has shifted over time, as consumers increasingly prefer minimally processed items. As a result, numerous non-thermal approaches have been implemented due to their potential to preserve the nutritional profile of products along with lengthening their storability. Microwaving, a green processing technique, volumetrically heats the product because of the interactions developed between charged ions, polar water molecules of foodstuff and the incoming electromagnetic waves. The study was mapped out to investigate the effect of microwave exposure time (60, 90 and 120 s) at fixed power (1000 W) and frequency (2450 MHz) on physicochemical properties, phytochemical constituents, antioxidant potential and microbial counts of lemon cordial stored at refrigerated temperature (4 ± 2 °C). The mentioned parameters were analyzed after an interval of 30–90 days. Statistical findings illustrated a highly significant (p ≤ 0.01) impact of microwave treatment and storage on titratable acidity, pH, total soluble solids, total phenolic contents, total flavonoids contents, antioxidant potential and total plate count. Sample microwaved for 120 s showed the highest pH values (2.45 ± 0.050), total soluble solids (56.68 ± 2.612 °B) and antioxidant activity (1212.03 ± 716.5 µg—equivalent of ascorbic acid per 100 mL of cordial); meanwhile, it exhibited the lowest total plate counts (1.75 ± 0.144 Log 10 CFU/mL). Therefore, microwaving can be suggested as a suitable alternate to traditional pasteurization techniques as well as to chemical preservatives.

Application and Effects of Ohmic-Vacuum Combination Heating on the Quality Factors of Tomato Paste

Ohmic-vacuum combination heating is a common method used in the food industry as a concentration process. In the present study, an OH-VC combination heating system was developed for producing tomato paste at temperatures of 70, 80, and 90 °C and pressure of 0.3, 0.5, and 0.7 bar and electric field of 1.82, 2.73, and 3.64 V/cm using a central composite design. The effects of heating conditions on the quality and sensory evaluation of tomato paste were also evaluated. Each combination of temperature, pressure, and the electric field was quantified for specific energy consumption, energy efficiency, and productivity. A decrease of 35.08% in the amount of acid ascorbic and lycopene content 19.01%, using conventional heating compared to ohmic-vacuum heating under optimized conditions, was attained. The results also highlighted an increase in the amount of HMF (69.79%) and PME (24.33%) using conventional heating compared to ohmic-vacuum heating under optimized conditions. Ascorbic acid, lycopene, titratable acidity, productivity, energy efficiency was higher than conventional heating; on the other hand, HMF, PME, pH, SEC were lower than conventional heating at the applied OH-VC process. No significant effects between OH-VC and conventional heating on the TSS were observed. In addition, OH-VC heating was highly efficient in the inhibition of bacterial growth. Further, a minor effect on the sensory properties of tomato paste with OH-VC heating compared to the conventional treatment. The obtained results indicate a strong potential for an OH-VC combination heating system as a rapid-heating, high-efficiency alternative for saving electrical energy consumption and preserving nutritional value.