Investigation on the effects of microwave and conventional heating methods on the phytochemicals of pomegranate (Punica granatum L.) and black mulberry juices

Polyphenol-Rich Extracts from Agroindustrial Waste and Byproducts: Results and Perspectives According to the Green Chemistry and Circular Economy

Polyphenols are natural secondary metabolites found in plants endowed with multiple biological activities (antioxidant, anti-inflammatory, antimicrobial, cardioprotective, and anticancer). In view of these properties, they find many applications and are used as active ingredients in nutraceutical, food, pharmaceutical, and cosmetic formulations. In accordance with green chemistry and circular economy strategies, they can also be recovered from agroindustrial waste and reused in various sectors, promoting sustainable processes. This review described structural characteristics, methods for extraction, biological properties, and applications of polyphenolic extracts obtained from two selected plant materials of the Mediterranean area as olive (Olea europaea L.) and pomegranate (Punica granatum L.) based on recent literature, highlighting future research perspectives.

Evaluation of the quality features of electrospray-coated pineapple slices with pomegranate and grape seed oil-enriched emulsions

The quality characteristics of pineapple slices coated with emulsions enriched with pomegranate seed oil (PSO) and grape seed oil (GSO) by electrospray coating (ESC) and dip-coating (DC) methods were investigated. The ESC method was evaluated as an alternative to conventional DC. Pineapple slices were stored in clear polystyrene cups for seven days at 5 °C and 80% RH. The weight loss (%), pH, titratable acidity, color, firmness, total antioxidant activity (TAA), total phenolic content (TPC), microbiological, and sensory qualities of fresh-cut pineapple slices were evaluated. Coated samples had significantly lower weight loss values than the non-coated samples after 7 days of storage. The usage of GSO-enriched emulsion with the ESC method was found to be more successful in preserving the titratable acidity. Although all the samples exhibited a significant decrease in yellowness (b*), the electrospray-coated pineapple slices had the highest. Incorporating GSO into the emulsions helped protect the tissue of the fresh-cut pineapples, regardless of the coating method used. The TPC and TAA values of the samples coated by the ESC method with emulsions enriched with PSO showed a lower decrease compared to other treatments. It was determined that the ESC method was more successful in preserving the sensory qualities of fresh-cut pineapples. These findings suggested that using ESC as a coating method with EO-enriched emulsions has positive effects on the quality features of fresh-cut pineapples.

Supplementary Information

The online version contains supplementary material available at 10.1007/s13197-023-05839-4.

Modeling of Sensory Properties of Poppy Sherbet by Turkish Consumers and Changes in Quality Properties during Storage Process

Poppy is an important edible plant containing bioactive components. This study aimed to produce good-tasting poppy sherbet by determining the content using a response surface methodology (RSM). At the same time, bioactive components, phenolic compounds, and color properties were investigated in optimum poppy sherbet during storage; 0.26 g of dried corn poppy flowers, 0.15 g of citric acid, and 4.29 g of sucrose values were the most promising, achieving high scores for color, smell, taste, and general acceptance from sensory properties (sensory score of 8.55 for color; 7.19 for smell; 8.38 for taste; 7.98 for general acceptability). A total of nine polyphenols were detected in the optimum poppy sherbet sample; gallic acid was the most common. There was no statistically significant difference between the samples stored on the 0th and 30th days regarding gallic acid content (23.886 ± 0.164 μg/mL, 23.403 ± 0.343 μg/mL) and protocatechuic acid (1.146 ± 0.048 μg/mL, 1.047 ± 0.038 μg/mL). Total flavonoid contents (TFC), total phenolic contents (TPC), CUPRAC (cupric ion reducing antioxidant capacity), DPPH (e free radical diphenylpicrylhydrazyl), total monomeric anthocyanin (TAC), and color values were found to decrease as the storage period increased. It was considered that a highly palatable and rich bioactive component product could be obtained.

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.

Effect of Blanching on Enzyme Inactivation, Physicochemical Attributes and Antioxidant Capacity of Hot-Air Dried Pomegranate (Punica granatum L.) Arils (cv. Wonderful)

Blanch-assisted hot-air drying of pomegranate arils with blanching treatments 90 °C for 30 s, 100 °C for 60 s, and unblanched (control) arils were investigated. Effects of blanching on enzyme inactivation (polyphenol oxidase and peroxidse), colour, texture, and other qualities of dried arils were discussed. The hot-air drying conditions were 60 °C, 19.6% relative humidity, and 1.0 m s−1 air velocity. Results showed that blanching reduced enzyme activity by 76% and 68% for blanched arils treated at 90 °C for 30 s and 100 °C for 60 s, respectively, compared to unblanched arils. With regard to the total colour difference (TCD), unblanched arils were 20.9% and 16.6% higher than blanched arils treated at 90 °C for 30 s and 100 °C for 60 s, respectively. Furthermore, the total soluble solids (TSS) for unblanched aril increased significantly from 16.1 to 24.9 °Brix after drying, followed by arils treated at 90 °C for 30 s and 100 °C for 60 s (21.4; 18.5 °Brix), respectively. Among the blanching treatments, dried arils treated at 90 °C for 30 s had the highest total anthocyanin content (28.6 mg C3gE/g DM), followed by 100 °C for 60 s (24.8 mg C3gE/g DM). Similarly, dried arils treated at 90 °C for 30 s had the highest radical scavenging activity (RSA) (32.1 mM TE/g DM) while the least was observed with unblanched arils (17.0 mM TE/g DM). Overall, the blanching treatment was more effective to maintain the quality attributes of pomegranate dried arils.

Degradation Kinetics of Anthocyanins from Purple Eggplant in a Fortified Food Model System during Microwave and Frying Treatments

A model food system was designed with dietary fiber and crude anthocyanins from purple eggplant peel to explore the degradation mechanism of anthocyanins during microwave and frying treatments. Our results found that delphinidin-3-O-rutinoside was either hydrolyzed into delphinidin or condensed with p-coumaric acid to form p-coumaroyl-delphinidin-3-O-glucoside. Delphinidin was cleaved into gallic acid and phloroglucinaldehyde, which might be further oxidized into pyrogallol and phloroglucinol, respectively. The total anthocyanin degradation followed the first-order kinetics in fried and microwaved solid matrix samples as well as microwaved liquid matrix samples. However, the total anthocyanin degradation followed the second-order kinetics in the heated liquid matrix samples at the frying temperature. The brown/polymeric color index, which negatively correlated with the anthocyanin content, increased faster in the liquid matrix samples than in the solid matrix samples. Compared with frying treatment, a higher rate of anthocyanin degradation in solution was observed under microwave treatment. However, anthocyanins were subject to much more damage under frying treatment than microwave treatment in a solid food system.

Anthocyanins, Vibrant Color Pigments, and Their Role in Skin Cancer Prevention

Until today, numerous studies evaluated the topic of anthocyanins and various types of cancer, regarding the anthocyanins' preventative and inhibitory effects, underlying molecular mechanisms, and such. However, there is no targeted review available regarding the anticarcinogenic effects of dietary anthocyanins on skin cancers. If diagnosed at the early stages, the survival rate of skin cancer is quite high. Nevertheless, the metastatic form has a short prognosis. In fact, the incidence of melanoma skin cancer, the type with high mortality, has increased exponentially over the last 30 years, causing the majority of skin cancer deaths. Malignant melanoma is considered a highly destructive type of skin cancer due to its particular capacity to grow and spread faster than any other type of cancers. Plants, in general, have been used in disease treatment for a long time, and medicinal plants are commonly a part of anticancer drugs on the market. Accordingly, this work primarily aims to emphasize the most recent improvements on the anticarcinogenic effects of anthocyanins from different plant sources, with an in-depth emphasis on melanoma skin cancer. We also briefly summarized the anthocyanin chemistry, their rich dietary sources in flowers, fruits, and vegetables, as well as their associated potential health benefits. Additionally, the importance of anthocyanins in topical applications such as their use in cosmetics is also given.

Perspective of Membrane Technology in Pomegranate Juice Processing: A Review

Pomegranate (Punica granatum L.) juice is well recognized for its high content of phytochemicals with proven health-promoting effects. Conventional processing techniques including clarification with fining agents, pasteurization and thermal concentration have significant influences on bioactive compounds and antioxidant activity of the juice. The growing consumers demand for high-quality pomegranate juice as well as the industrial interest for the production of functional foods, nutraceuticals, and cosmetics from its bioactive compounds have promoted the interest for minimal processing technologies. In this context, membrane-based operations represent an innovative approach to improve the overall quality of pomegranate juice production. This review focuses on the recent advances and developments related to the application of membrane technology in pomegranate juice processing. Conventional pressure-driven membrane operations and innovative membrane operations, such as osmotic distillation and pervaporation, are discussed in relation to their potential in juice clarification, fractionation, concentration and aroma recovery. Their implementation in integrated systems offer new opportunities to improve the healthiness and quality of the juice as well as to recover, purify and concentrate bioactive compounds for the formulation of functional ingredients.

Thermostability of the visual color and anthocyanins from Rio-Grande-Cherry (Eugenia involucrata DC)

Abstract The extract of Rio-Grande-Cherry (Eugenia involucrata DC), pure and with stevia addition (0.75% and 1.5%) and sucrose addition (20% and 40%), was subjected to heat treatment at 10 °C, 25 °C and between 50 °C and 90 °C. Anthocyanins and the color parameters C* and TCD (total color difference) followed first-order reaction kinetics while h° followed a zero order kinetic model, under all conditions. The addition of sweeteners, through the reduction of water activity, influenced the thermal stability of the anthocyanins and of the color parameters C*, h° and TCD was the most pronounced effect in the latter. The lower the temperatures, the most relevant was the effect of the sweeteners on increasing half-life. Thermodynamically, the degradation reaction of anthocyanins was defined as endothermic, as well as non-spontaneous and transition state of the molecules more structurally organized than the reactants.

Effects of Drying Methods on the Content, Structural Isomers, and Composition of Astaxanthin in Antarctic Krill

Antarctic krill (Euphausia superba) is one of the important bioresources in Antarctic waters, containing many bioactives (e.g., astaxanthin), which have a highly potential value for commercial exploitation. In this study, the effects of processing methods on the content, structural isomers, and composition of astaxanthins (free astaxanthin and astaxanthin esters) were studied. Three drying methods, comprising freeze-drying, microwave drying, and hot-air drying, were used. Free astaxanthin (Ast), astaxanthin monoesters (AM), and astaxanthin diesters (AD) in boiled krill (control) and dried krill were extracted and analyzed using high-resolution mass spectrometry with ultraviolet detection. After the three processes, total astaxanthin loss ranged from 8.6 to 64.9%, and the AM and AD contents ranged from 78.3 to 16.6 and 168.7 to 90.5 μg/g, respectively. Compared to other kinds of astaxanthin esters, astaxanthin esters, which linked to eicosapentaenoic acid and docosahexaenoic acid, as well as the Ast, were more easily degraded, and AM was more susceptible to degradation than AD. All-E-astaxanthin easily transformed to the 13Z-astaxanthin than to the 9Z-astaxanthin during the drying process, but the proportions of optical isomers changed due to drying by no more than 5%. The results suggested that freeze-drying, low-power microwave drying (≤1 kW), and low-temperature hot-air drying (≤60 °C) are optimal drying methods for ensuring the quality of krill products.

Effects of Vacuum Ohmic Evaporation on Some Quality Properties of Sour Cherry Juice Concentrates

Sour cherry juice (SJ) having total soluble solid (TSS) content of 19.2 % was concentrated to 65 % TSS by applying vacuum ohmic evaporation (VOE) and vacuum evaporation (VE) methods under constant absolute pressure (25 kPa). Total monomeric anthocyanin content (TMAC) of sour cherry concentrate (65 % TSS) was found in the range of 1561.67–1777.38 mg/L whereas total phenolic content (TPC) varied in the range of 9,071.22–78,347.53 mg/L concentrate. TPC and TMAC values of juice concentrates were affected less from VOE process compared to VE (p < 0.05) while there was no significant difference between the total antioxidant activities of SJ concentrates obtained by both methods (p > 0.05). TMAC and TPC values increased as the voltage gradient applied increased (p < 0.05). VOE process preserved the color properties of juice concentrates better compared to the VE process. It was concluded that VOE method could be an alternative fast evaporation method to obtain high-quality fruit juice concentrates.

Zingiber officinale Extract (ZOE) Incorporated with Layered Double Hydroxide Hybrid through Reconstruction to Preserve Antioxidant Activity of ZOE against Ultrasound and Microwave Irradiation

We prepared Zingiber officinale extract (ZOE) incorporated in a layered double hydroxide (LDH) hybrid through a reconstruction method in order to preserve the antioxidant activity of ZOE from ultrasound and microwave irradiation. X-ray patterns, infrared spectroscopy, and scanning electron microscopy suggested that ZOE moieties were encapsulated in the interparticle space of reconstructed LDH, thus preserving its intact structure. Dynamic light scattering and zeta-potential measurement also supported the hypothesis that ZOE moieties were located in the interparticle pore of LDH rather than at the surface of LDH particles. Thermogravimetry analysis revealed that thermal stability of encapsulated ZOE could be enhanced by LDH encapsulation. Radical scavenging assay showed that antioxidant activity of ZOE-LDH hybrid was increased after ultrasound and microwave irradiation, while ZOE itself dramatically lost its antioxidant activity upon ultrasound and microwave treatment.

Phenolic compounds participating in mulberry juice sediment formation during storage

The stability of clarified juice is of great importance in the beverage industry and to consumers. Phenolic compounds are considered to be one of the main factors responsible for sediment formation. The aim of this study is to investigate the changes in the phenolic content in clarified mulberry juice during storage. Hence, separation, identification, quantification, and analysis of the changes in the contents of phenolic compounds, both free and bound forms, in the supernatant and sediments of mulberry juice, were carried out using high performance liquid chromatographic system, equipped with a photo-diode array detector (HPLC-PDA) and HPLC coupled with quadrupole-time of flight mass spectrometric (HPLC-QTOF-MS/MS) techniques. There was an increase in the amount of sediment formed over the period of study. Total phenolic content of supernatant, as well as free phenolic content in the extracts of the precipitate decreased, whereas the bound phenolic content in the sediment increased. Quantitative estimation of individual phenolic compounds indicated high degradation of free anthocyanins in the supernatant and sediment from 938.60 to 2.30 mg/L and 235.60 to 1.74 mg/g, respectively. A decrease in flavonoids in the supernatant was also observed, whereas the contents of bound forms of gallic acid, protocatechuic acid, caffeic acid, and rutin in the sediment increased. Anthocyanins were the most abundant form of phenolics in the sediment, and accounted for 67.2% of total phenolics after 8 weeks of storage. These results revealed that phenolic compounds, particularly anthocyanins, were involved in the formation of sediments in mulberry juice during storage.

Phytochemical composition and in vitro antioxidant potential of Cynodon dactylon leaf and rhizome extracts as affected by drying methods and temperatures

The effect of five drying methods including shade drying (SHD), solar drying (SOD), and oven drying at 30 (OD30), 40 (OD40) and 50 °C (OD50) on the phytochemical composition and antioxidant potential of C. dactylon leaf and rhizome was assessed. Among drying methods, OD50 resulted in the shortest drying time (18.3 and 12 h for rhizome and leaf, respectively), when compared with SHD and SOD. Based on GC-MS analyses, 15 and 17 constituents were identified in leaf and rhizome extracts, respectively, accounting for ~ 99% of all components. Fatty acids (palmitic acid and linoleic acid) along with their methyl esters (ethyl palmitate, ethyl linoleate and ethyl oleate) and other derivatives (dihomo-γ-linoleic acid) were the main identified constituents shortly after drying procedures; however, other components such as 5-hydroxymethylfurfural, maltol, retinol and phytol were also traced. Some of C. dactylon phytochemicals including 5-hydroxymethylfurfural and ethyl linoleate were sensitive to high drying temperatures. Besides, higher drying temperatures lead to the production or increasing the level of substances such as 2,3-dihydrobenzofuran, tricyclopentadeca-3,7-dien and 2,3-dihydro-3,5-dihydroxy-6-methyl-4H-pyran-4-one and diacetin. Based on the 2,2-diphenyl-1-picrylhydrazyl (DPPH) free radical scavenging assay, the IC50 values were generally higher (significance level of 0.05) for oven-dried rhizome compared with shade-dried leaves and rhizomes that quenched more than 84% of the DPPH at the concentration of 400 mg/ml (IC50 59.12). Our findings suggest that OD30 is a versatile drying method not only to reduce drying time but also to preserve the main phytochemicals and antioxidant activity of C. dactylon during dehydration.

Processing black mulberry into jam: effects on antioxidant potential and in vitro bioaccessibility

BACKGROUND

Black mulberries (Morus nigra) were processed into jam on an industrialised scale, including the major steps of: selection of frozen black mulberries, adding glucose-fructose syrup and water, cooking, adding citric acid and apple pectin, removing seeds, and pasteurisation. Qualitative and quantitative determinations of antioxidants in black mulberry samples were performed using spectrophotometric methods, as well as HPLC- and LC-QTOF-MS-based measurements. These analyses included the determination of total polyphenolic content, % polymeric colour, total and individual anthocyanin contents, antioxidant capacity, and in vitro bioaccessibility in processing samples.

RESULTS

Jam processing led to a significant reduction in total phenolics (88%), total flavonoids (89%), anthocyanins (97%), and antioxidant capacity (88-93%) (P < 0.05). Individual anthocyanin contents, determined using HPLC analysis, also showed a significant decrease (∼99% loss). In contrast, % recovery of bioaccessible total phenolics, anthocyanins, and antioxidant capacity (ABTS assay) increased after jam processing (16%, 12%, and 37%, respectively).

CONCLUSION

Fruit processing resulted in losses of polyphenols, anthocyanins, and antioxidant capacity of black mulberry jam. Optimisation of food processing could help to protect the phenolic compounds in fruits which might be helpful for the food industry to minimise the antioxidant loss and improve the final product quality. © 2016 Society of Chemical Industry.

Protective Effects of Amarogentin against Carbon Tetrachloride-Induced Liver Fibrosis in Mice

Amarogentin, a secoiridoid glycoside that is mainly extracted from Swertia and Gentiana roots, has been suggested to exhibit many biological effects, including anti-oxidative, anti-tumour, and anti-diabetic activities. The present study was designed to evaluate the protective effects of amarogentin on carbon tetrachloride-induced liver fibrosis in vivo and the underlying mechanism. Fibrosis was induced by subcutaneous injections of 6 mL/kg of 20% carbon tetrachloride (dissolved in olive oil) twice per week for seven weeks. Mice were orally treated with 25, 50, and 100 mg/kg amarogentin and with colchicine as a positive control. Biochemical assays and histopathological investigations showed that amarogentin delayed the formation of liver fibrosis; decreased alanine aminotransferase, aspartate aminotransferase, malondialdehyde and hydroxyproline levels; and increased albumin, cyclic guanosine monophosphate, glutathione peroxidase, and superoxide dismutase levels. Moreover, amarogentin exhibited downregulation of α-smooth muscle actin and transforming growth factor-β₁ levels in immunohistochemical and Western blot analyses. The levels of phosphorylated extracellular regulated protein kinases, c-Jun N-terminal kinase, and p38 were also significantly reduced in all amarogentin-treated groups in a dose-dependent manner. These findings demonstrated that amarogentin exerted significant hepatoprotective effects against carbon tetrachloride-induced liver fibrosis in mice and suggested that the effect of amarogentin against liver fibrosis may be by anti-oxidative properties and suppressing the mitogen-activated protein kinase signalling pathway.

Cyanidin-3-O-glucoside: Physical-Chemistry, Foodomics and Health Effects

Anthocyanins (ACNs) are plant secondary metabolites from the flavonoid family. Red to blue fruits are major dietary sources of ACNs (up to 1 g/100 g FW), being cyanidin-3-O-glucoside (Cy3G) one of the most widely distributed. Cy3G confers a red hue to fruits, but its content in raspberries and strawberries is low. It has a good radical scavenging capacity (RSC) against superoxide but not hydroxyl radicals, and its oxidative potential is pH-dependent (58 mV/pH unit). After intake, Cy3G can be metabolized (phases I, II) by oral epithelial cells, absorbed by the gastric epithelium (1%-10%) and it is gut-transformed (phase II &amp; microbial metabolism), reaching the bloodstream (<1%) and urine (about 0.02%) in low amounts. In humans and Caco-2 cells, Cy3G's major metabolites are protocatechuic acid and phloroglucinaldehyde which are also subjected to entero-hepatic recycling, although caffeic acid and peonidin-3-glucoside seem to be strictly produced in the large bowel and renal tissues. Solid evidence supports Cy3G's bioactivity as DNA-RSC, gastro protective, anti-inflammatory, anti-thrombotic chemo-preventive and as an epigenetic factor, exerting protection against Helicobacter pylori infection, age-related diseases, type 2 diabetes, cardiovascular disease, metabolic syndrome and oral cancer. Most relevant mechanisms include RSC, epigenetic action, competitive protein-binding and enzyme inhibition. These and other novel aspects on Cy3G's physical-chemistry, foodomics, and health effects are discussed.