Effect of microwave blanching on antioxidant activity, phenolic compounds and browning behaviour of some fruit peelings

Systems Pharmacology Study of the Anti-Liver Injury Mechanism of Citri Reticulatae Pericarpium

Liver diseases are mostly triggered by oxidative stress and inflammation, leading to extracellular matrix overproduction and prone to develop into liver fibrosis, cirrhosis and hepatocellular carcinoma. Liver injury (LI) refers to various pathogenic factors leading to the destruction of stem cells that then affect the liver's normal function, causing a series of symptoms and abnormal liver function indicators. Citri Reticulatae Pericarpium (CRP) is one of the most commonly used traditional Chinese medicines; it contains flavonoids including hesperidin, nobiletin, and tangeretin. CRP has antibacterial, antioxidant, and antitumor effects that reduce cholesterol, prevent atherosclerosis and decrease LI. Here we analyzed the components of CRP and their targets of action in LI treatment and assessed the relationships between them using a systems pharmacology approach. Twenty-five active ingredients against LI were selected based on ultra-performance liquid chromatography-quadrupole/time-of-flight mass spectrometry results and databases. The drug targets and disease-related targets were predicted. The 117 common targets were used to construct a protein-protein interaction network. We identified 1719 gene ontology items in LI treatment, including 1,525 biological processes, 55 cellular components, and 139 molecular functions. These correlated with 49 Kyoto Encyclopedia of Genes and Genomes pathways. These findings suggest that CRP may counteract LI by affecting apoptotic, inflammatory, and energy metabolism modules. In vitro experiments suggested that the mechanism may involve hesperidin and naringenin acting on CASP3, BAX, and BCL2 to affect the apoptosis pathway, attenuating liver fibrosis. Naringenin significantly inhibited AKT1 phosphorylation, which in turn mediated activation of the phosphoinositide 3-kinase-Akt signaling pathways against LI. This study provides a reference for systematically exploring the mechanism of CRP's anti-LI action and is also expands of the application of systems pharmacology in the study of traditional Chinese medicine.

Intensification of bio-actives extraction from pomegranate peel using pulsed ultrasound: Effect of factors, correlation, optimization and antioxidant bioactivities

Pomegranate peel (PP) is one of the interesting agri-food by-products because of its abundant bioactive phytochemicals. However, the bioactivity of valuable compounds is affected due to the extraction method used. A pulsed ultrasound-assisted extraction (PUAE) was carried out to intensify the extraction efficacy with reduced power and time. Influence of several process variables viz. peel solids/ solvent ratio, sonication power, duty cycle, and extraction time was studied using empirical quadratic models followed by multicriterial numerical optimization with respect to face-centered composite design. Power-duty cycle combination was found to be most significant (p < 0.05) for process intensification. The optimal process conditions of 2.17 g/100 mL S/S ratio at 116 W power with 80% duty cycle for 6 min resulted into 0.48 g/g yield, 177.54 mg GAE/g total phenolics content, 35.71 mg QE/g total flavonoids, 160.54 mg GAE/g antioxidant capacity, 21.65 mg cyn-3-glc/100 g anthocyanin content with 54.92 browning index in dry pomegranate peel. Significant Pearson correlation analysis was established in all responses with potent phenols and flavonoid relation with highest coefficient (r) 0.931. All response models were significantly validated with regression coefficient (R2) above 0.965. Remarkable antioxidant bioactivities were recorded for the resultant peel extract. Hence, it is strongly recommended that PUAE could be successfully applied for the intensification of the extraction process of bioactive from any peel and or plant systems with minimal process time and power consumption with a green label.

Application of a novel microwave energy treatment on brewers' spent grain (BSG): Effect on its functionality and chemical characteristics

The effect of a new microwave energy treatment on brewers' spent grain (BSG) functionality and its application in a bakery product was evaluated. The physicochemical modifications of BSG were studied with special emphasis on the analysis of non-enzymatic browning reactions. Microwave treatment induced the formation of Maillard reaction products with a high antioxidant activity. The structure of these compounds was fully analyzed and it was concluded that melanoidins were formed by polymerization of furanose rings. Results indicated that chlorogenic acids were also reactants involved in the development of this reaction, leading to the formation of new bioaccesible compounds with important antioxidant activity. Although the addition of BSG in cookie formulations negatively affect their texture, this effect was successfully reduced when the microwave treatment was applied on BSG. This was associated to the disrupting effect that the microwaves had on BSG fiber, which significantly reduced its water absorption index (p ≤ 0.05).

Recent Trends in Pretreatment of Food before Freeze-Drying

Drying is among the most important processes and the most energy-consuming techniques in the food industry. Dried food has many applications and extended shelf life. Unlike the majority of conventional drying methods, lyophilization, also known as freeze-drying (FD), involves freezing the food, usually under low pressure, and removing water by ice sublimation. Freeze-dried materials are especially recommended for the production of spices, coffee, dried snacks from fruits and vegetables and food for military or space shuttles, as well as for the preparation of food powders and microencapsulation of food ingredients. Although the FD process allows obtaining dried products of the highest quality, it is very energy- and time consuming. Thus, different methods of pretreatment are used for not only accelerating the drying process but also retaining the physical properties and bioactive compounds in the lyophilized food. This article reviews the influence of various pretreatment methods such as size reduction, blanching, osmotic dehydration and application of pulsed electric field, high hydrostatic pressure or ultrasound on the physicochemical properties of freeze-dried food and drying rate.

Phenolic Compounds in Mesoamerican Fruits-Characterization, Health Potential and Processing with Innovative Technologies

Diets rich in phenolic compounds have been associated to reducing the risk of metabolic syndrome and its derived disorders. Fruits are healthy components of the human diet because of their vitamin, mineral, fiber and phenolic profile. However, they have a short shelf-life which is limited by microbiological growth and enzymatic activity. Innovative preservation methods such as high hydrostatic pressure, pulsed electric fields, ultrasound, microwave, cold plasma and ultraviolet light have become popular for the processing of fruits because they can preserve nutritional quality. In this review, the phenolic profile and health potential of 38 Mesoamerican fruits were assessed. Phenolic compounds were classified based on their contribution to the diet as flavonoids, phenolic acids, tannin, lignins and stilbenoids. Due to this composition, fruits showed a wide range of bioactivities which included anti-inflammatory, anti-diabetic, anti-hypertensive and anti-obesity activities, among others. Phenolic content in fruits submitted to innovative food processing technologies depended on parameters such as enzymatic activity, antioxidant capacity, microstructure integrity and cell viability. Innovative technologies could increase phenolic content while assuring microbiological safety by (i) promoting the release of bound phenolic compounds during processing and (ii) inducing the synthesis of phenolic compounds by activation of phenylpropanoid pathway during storage.

Effect of blanching pretreatment and microwave-vacuum drying on drying kinetics and physicochemical properties of purple-fleshed sweet potato

In this study, drying kinetics and quality of purple-fleshed sweet potato (PFSP) subjected to microwave-vacuum drying were investigated. The effects of hot water and steam blanching pretreatment on physicochemical characteristics of the dried products were also considered. The samples were dehydrated in a custom-made microwave-vacuum system at different power levels including 450, 600 and 850 W. Hot air drying at 70 °C was also conducted for comparison. The results showed that drying time of PFSP under microwave-vacuum conditions ranged from 6 to 12 min, significantly reduced as compared to that of hot air drying (600 min). The improvement of drying rate was also evidenced by increased effective moisture diffusivity (2.22 × 10^-7-4.05 × 10^-7 m²/s) of the samples. Drying kinetics of PFSP was best fitted by Page and logarithmic model with R² ranging from 0.991 to 0.998, and RMSE from 0.016 to 0.030. PFSP dried under microwave-vacuum condition had lower water absorption index and swelling capacity than hot air drying. Color, antioxidant activity and total phenolic content of dried PFSP were also improved under microwave-vacuum drying. The effects of blanching pretreatment on quality of dried PFSP were more dominant in hot air than microwave-vacuum dried samples.

The Effects of Morus alba L. Fortification on the Quality, Functional Properties and Sensory Attributes of Bread Stored under Refrigerated Conditions

Mulberry is one of the most beneficial plant of our planet for sustainable development. White mulberry (Morus alba L.) is widely recognized for its health-promoting properties. It is characterized by a high content of bioactive compounds, mainly flavonoids, and has a strong antioxidant effect, and thus can have a beneficial effect on health. The aim of the study was to evaluate the effect of freezing storage of bread with the addition of extract from mulberry leaves and fruits on the content of polyphenols, antioxidant activity and sensory properties. The stored bread with mulberry addition was characterized by high content of phenolic compounds, reducing and chelating activity and antiradical activity. The addition of mulberry had greater effect on the increase in the content of protocatechuic and chlorogenic acids, and isoquercetin among the flavonols. Bread enriched with mulberry was microbiologically clean and sensory accepted both after baking and after 30 days of storage under refrigerated conditions. White mulberry is a raw material which can be used as an addition to enrich refrigerated bread. The use of the extract and mulberry fruit to fortify bread is consistent with the principle of sustainable development due to the use of raw materials which are a good source of compounds contributing to the improvement of the well-being of the population.

Effects of vacuum-steam pulsed blanching on drying kinetics, colour, phytochemical contents, antioxidant capacity of carrot and the mechanism of carrot quality changes revealed by texture, microstructure and ultrastructure

An emerging blanching technology, namely vacuum-steam pulsed blanching (VSPB) was employed to blanch the carrots and its effects on blanching efficiency, microstructure and ultrastructure, drying kinetics, colour, texture, phytochemicals (phenolics and β-carotene) and antioxidant capacity of carrot slices were explored and compared with the traditional hot water blanching. Results showed that both blanching treatments enhanced the drying velocity and shortened the drying time by 25.9% compared with untreated samples. VSPB yielded higher blanching efficiency, better colour (more red and yellow), greater antioxidant capacity and higher preservation of phytochemicals compared with hot water blanched samples. Especially, compared to hot water blanched carrots, the p-hydroxybenzoic acid, ferulic acid, and caffeic acid content of VSPB samples increased of 106.6%, 42.0%, and 19.0%, respectively. Interestingly, the chlorogenic acid content in the blanched carrot increased more than 220 times compared to fresh samples. Ultrastructure and microstructure observation clarify the mechanism of quality enhancement of VSPB.

Valorisation of Camellia sinensis branches as a raw product with green technology extraction methods

This work deals with the study of tea stalks from pruning debris using environmental friendly extraction technology to offer new healthy properties. In the manufacturing tea industry, tea trees require to be pruned every year and most of their remains are discarded as a waste with no economic value. Microwave aqueous extraction and pressurized hot water extraction process (autohydrolysis) were used to recover bioactive compounds from the tea branches. Operating at a fixed solid: liquid ratio (1:15), the effect of the maximum heating temperatures from 140 to 220 °C was studied. Liquid extracts were analysed for total phenolic, oligosaccharides, protein, mineral and heavy metals content, as well as for antioxidant capacity. The antitumoral possibilities were also determined for selected samples. The obtained results indicated that both processes could be used as an alternative to recover bioactive compounds from tea wastes, although microwave-assisted extraction allowed saving time when compared with autohydrolysis processing. The temperature exhibited a relevant effect on the total phenolic content and antioxidant capacity, decreasing with the microwave treatment and increasing with the autohydrolysis temperature. The obtained extracts could be adequate for incorporation in food and non-food fields.

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Tea pruning remains were valorised using green extractions by microwave (MW) and autohydolysis (AH).

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MW and AH were efficient technologies to recover bioactive compounds.

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Values above 40 mg gallic acid equivalents/g extract and 0.10 g Trolox/g extract were identified.

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Future applications in cosmetics, pharmacy or food industries should be explored.