Red grape pomace (RGP) and onion solid wastes (OSW) were used as raw material to produce flavonoid-enriched extracts, using ultrasound-assisted solid-liquid extraction. The extraction medium used was composed of water and glycerol and under the conditions used the extraction of flavonoids from both materials was shown to obey first-order kinetics. Maximum diffusivities (De) values were 4.01 × 10−11 and 2.35 × 10−11 m2·s−1, for RGP and OSW extraction, respectively, while the corresponding activation energies (Ea) were 14.00 and 15.23 kJ·mol−1.

This work discusses hydrolysis of defatted grape in supercritical water (SCW) at 380 °C and 260 bar from 0.18 s to 1 s focusing attention to sugars recovery in the liquid phase of the product and detailed characterization of remaining solid phase enriched in polyaromatics (e.g. lignin, flavonoids, etc.). After the longest reaction time of 1 s, 56% of carbohydrates could be recovered in the liquid phase, as a result of carbohydrate hydrolysis. The high content of insoluble lignin in biomass (36%), acts as a mass transfer limitation and presents an important feature in the hydrolysis process, slowing down the conversion of carbohydrate fraction, as after the maximum time of 1s, 10% of carbohydrates still remained in the solid phase. Milled wood lignin, extracted from biomass and dioxane extract from the solid phase were characterized in order to understand the main structural changes during the SCW hydrolysis process. Dioxane (80%) extraction of solids produces a very complex mixture of lipophilic extractives, flavonoids and lignin with a certain amount of chemically linked carbohydrates. 2D NMR analysis of dioxane extract shows remarkably subtle changes in the amounts of main lignin moieties (β-O-4′, β-β’ (resinol) and β-5 (phenylcoumaran)). This subtle change of the main lignin structures is an important feature in the further valorisation of this sulfur-free lignin residue.

There has been a growing interest in developing effective strategies to inhibit lipid oxidation in emulsified food products by utilization of natural phenolic antioxidants owing to their growing popularity over the past decades. However, due to the complexity of emulsified systems, the inhibition mechanism of phenolic antioxidants against lipid oxidation is rather complicated and not yet fully understood. In order to highlight the importance of polarity of phenolic antioxidants in emulsified systems according to the polar paradox, this review covers the recent progress on chemical, enzymatic, and chemoenzymatic lipophilization techniques used to modify the polarity of antioxidants. The partitioning behavior of phenolic antioxidants at the oil–water interface, which can be influenced by the presence of synthetic surfactants and/or antioxidant emulsifiers (e.g., polysaccharides, proteins, and phospholipids), is discussed. In addition, the emerging phenolic antioxidants among phenolic acids, flavonoids, tocopherols, and stilbenes applied in food emulsions are elaborated. As well, the interactions of polar–nonpolar antioxidants are stressed as a promising strategy to induce synergistic interactions at oil–water interface for improved oxidative stability of emulsions.

The valorisation and management of agri‐food waste are currently hot investigation topics which probe the recovery of valuable compounds, such as polyphenols. In this study, high‐pressure/high‐temperature extraction (HPTE) and ultrasound‐assisted extraction (UAE) have been used to study the recovery of phenolic compounds from grape marc and olive pomace in hydroalcoholic solutions. The main phenolic compounds in both extracts were identified by HPLC‐DAD. Besides extraction yield (total polyphenol and flavonoid content) and the antiradical power, polyphenol degradation under HPTE and UAE has also been studied. HPTE with ethanol 75% gave higher phenolic extraction yields: 73.8 ± 1.4 mg of gallic acid equivalents per gram of dried matter and 60.0 mg of caffeic acid equivalents per gram of dried matter for grape marc and olive pomace, respectively. In this study, the efficient combination of ethanol/water mixture with HPTE or UAE has been used to enhance the recovery of phenolic compounds from grape marc and olive pomace. HPLC‐DAD showed that UAE prevents phenolic species degradation damage because of its milder operative conditions.

Food colorants are an important class of food additives that give the first impression to consumers about the quality of food. Ce(IV)-reducing antioxidant capacity assay originally developed in our laboratories was adapted to the determination of synthetic food colorants for the first time. This method allowing for total antioxidant capacity assay of dietary polyphenols, flavonoids, and ascorbic acid in plant extracts is based on the room temperature oxidation of antioxidant compounds with Ce(IV) sulfate in dilute H2SO4 solution and measurement of the absorbance of unreacted Ce(IV) at 320 nm. The results of the proposed method were correlated with high-performance liquid chromatography (HPLC) findings. Individual standard solutions, synthetic mixtures of synthetic colorants, and colorant extracts were identified and quantified with HPLC on a C18 column equipped with a diode array detector, and slight modifications on the existing HPLC method were made to analyze synthetic colorant mixtures. This work proposes Ce(IV)-oxidative spectrophotometry as a complementary technique to HPLC in the analysis of food colorants.

Slightly acidic electrolyzed water (SAEW) with available chlorine concentrations (ACC) of 35 and 70 mg/L is used instead of regular production water for soaking pea (Pisum sativum L.) seeds and spraying the sprouts during seed sprouting. Sodium hypochlorite (NaOCl) with the same ACC and tap water are used as a control in this study. The population of total bacteria, coliform, yeast and mold are determined at day 2, day 5, day 8, and day 11, respectively during seed sprouting. The biological indicators, nutritive indicators, and nitrite content after the sprouts are harvested are measured as well. The results indicate that when treated with SAEW, the counts of total bacteria, coliform, yeast and mold are reduced by 0.99–1.58 log CFU/g, 0.57–1.02 log CFU/g, and 1.01–1.22 log CFU/g respectively, compared to tap water treatment. Fresh weight, length, and edible rate of the sprouts significantly improve when treated with SAEW (p < 0.05). No evident adverse effects are observed in the nutritive indicators after SAEW treatment. In fact, a slight improvement (soluble sugar, flavonoid) was evident. Moreover, after a storage period of 7 d, the nitrite content of the sprouts was significantly lower in the SAEW treated samples than in any of other treatments. Therefore, SAEW could be a promising application in the production of pea sprouts to ultimately improve food safety.

Abstract Following a request from the European Commission, the EFSA Panel on Nutrition, Novel Foods and Food Allergens (NDA) was asked to deliver an opinion on the safety of ‘Hovenia dulcis fruit extract’ as a novel food (NF) for its use in food supplements. The NF concerns a hot water extract of sliced and dried fruits and peduncles of Hovenia dulcis Thun. The production process is described in sufficient detail but contains contradictory information regarding the mixing with another ingredient of the NF. The NF is comprised of mostly carbohydrates (about 90%), about 2% proteins, 5% moisture, less than 1% fat and about 2% ash. In addition, the NF contains small amounts of flavonoids such as dihydromyricetin, myricetin and quercetin. The Panel notes limitations of the data provided from the batch testing regarding proximate analyses and plant secondary metabolites. Given these limitations, the Panel considers that the data provided by the applicant do not demonstrate that different batches produced with the described production process meet the proposed specifications. The target population is the general adult population excluding pregnant and lactating women and people with a chronic disease, such as liver malfunction. Limited information was provided on a history of consumption of Hovenia dulcis fruits and on an extract approved in South Korea. A number of toxicological studies were performed. However, the study reports did not allow to verify that the test item was representative of the NF. The same applied to a human study provided by the applicant. The Panel concludes that the safety of the NF has not been established.