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BACKGROUND: The effect of leaf removal on postharvest performance of dehydrated grapes has been poorly analyzed. The aim of this study was to evaluate the effect of leaf removal at veraison stage on the metabolites of fresh and dehydrated grapes of two indigenous Cypriot cultivars ('Mavro' and 'Xynisteri'), which are destined for the production of 'Commandaria', a protected designation of origin (PDO) premium sweet wine. RESULTS: Leaf removal led to a reduction of soluble solids, titratable acidity, aroma potential and most of the phenolic groups in the musts of both cultivars. Dehydration led to a significant increase in all of these parameters in both cultivars, being more pronounced in cv. 'Mavro'. Interestingly, leaf removal indicated differential response in the dehydrated product of the cultivars examined; liquid chromatography (LC‐DAD‐qTOF‐MS) data showed a significant decrease in phenolic compounds in 'Xynisteri' must (from 66.73 to 44.15 mg L−1), while 'Mavro' must registered similar values of phenolic compounds (from 94.78 to 96.72 mg L−1), but with a different distribution among phenolic groups. Intriguingly, flavonols and flavan‐3‐ols that present significant health‐promoting properties showed higher concentrations in the must from dehydrated 'Mavro' grapes that were subjected to preharvest leaf removal. CONCLUSIONS: Leaf removal at veraison stage followed by sun drying differentially affected the chemical composition of the examined cultivars. This preharvest application followed by postharvest dehydration was beneficial for cv. 'Mavro', while this was not the case for cv. 'Xynisteri'. The effects of leaf removal in other developmental stages (i.e. pre/post bloom stage) need to be dissected with the ultimate goal of providing an end product with high bioactive content. © 2018 Society of Chemical Industry [ABSTRACT FROM AUTHOR]

The objective of this study was to compare the effect of traditional sun-drying method (TM) with four alternative dehydration methods [(a) multiple horizontal wires (MHW), (b) multiple vertical pallets (MVP), (c) low greenhouse (LGH) and (d) hot-air dryer treatment (HAD)] on phenolic composition, oenological parameters, aroma potential and browning compounds of musts obtained from dehydrated grapes ( Vitis vinifera cv. ‘Xynisteri’). Dehydrated grapes of the examined cultivar are being used to produce ‘Commandaria’ dessert wine, a protected designation of origin product in Cyprus. LGH and HAD treatments led to a significant reduction of the dehydration period. Soluble solid contents were used to monitor the progress of dehydration process; no changes among the examined dehydration methods in reducing sugar composition were found. Notably, HAD led to a dramatic rise (3.2-fold) of titratable acidity that was obviously not related only to the concentration effect. Furthermore, all dehydration methods concentrated total bound volatiles and induced the formation of brown pigments. Based on the Folin-Ciocalteu index, only HAD and LGH induced a significant increase in total phenolic content in dehydrated grape musts. Subsequently, forty phenolic compounds were identified and quantified by LC-DAD-qTOF-MS. Results showed a significant effect of dehydration methods that vary according to the different groups of phenolic compounds considered. Similarly to Folin-Ciocalteu index, HAD and LGH methods increased significantly the phenolic content in grape musts, whereas MHW and MVP methods increased it slightly higher than the concentration factor. Flavonols, flavan-3-ols and flavanonols were the most affected polyphenolic groups. A significant increment of hydroxybenzoic and hydroxycinnamic acids, the predominant groups of phenolic compounds found in ‘Xynisteri’ grapes, was monitored. Taking into consideration that HAD cannot be exploited under the existing legal framework, LGH showed the greatest potential for the production of high quality dehydrated ‘Xynisteri’ grape must. [ABSTRACT FROM AUTHOR]

Grapes's sun-dried process is one of the most critical steps in the production of ‘Commandaria’, a dessert wine product that is exclusively produced in Cyprus and derived from must obtained from two indigenous grape cultivars, namely ‘Mavro’ and ‘Xynisteri’. Despite its significant economic importance, no data regarding the primary and secondary metabolites of the aforementioned cultivars exist. Thus, in the current study, the effect of sun drying process on the qualitative attributes and phenolic profile of ‘Mavro’ and ‘Xynisteri’ musts was dissected. Musts were analyzed at harvest and at the end of the sun-drying process that corresponds to ca. 30–40% water loss. Results highlighted significant differences in chemical composition of the must before and after the sun-drying process. Except for the increase of soluble solids content, a significant increment in glucose, fructose, total acidity, total phenols and total flavonoids contents was monitored. Subsequently, forty-two phenolic compounds were identified by LC-DAD-qTOF-MS revealing the polyphenolic fingerprint of the two cultivars. Results also indicated that changes in the phenolic composition of the obtained must are not only correlated with the dehydration effect, but both synthesis or degradation reactions occurred. In particular, the increases in the concentration of hydroxybenzoic acids were higher than the concentration effect for both cultivars. Regarding to hydroxycinnamates, dehydration caused a six-fold increase of hydroxycinnamic acid content in both cultivars. Intriguingly, the concentration of some hydroxycinnamic acids such as caffeic acid dihexoside and fertaric acid isomer went descending. Although the degradation of the internal side of the skin facilitate improved extractability from the skins to the grape pulp and therefore to the grape must, the sun-drying process may also induced stilbene and lignans synthesis production. A significant effect of dehydration on the postharvest biosynthesis of three groups of flavonoids (flavonols, flavan-3-ols, flavanonols), was also observed. This study sheds some light in the substantial changes that occur in specific metabolites during the sun drying process; such metabolites can be considered as potential factors that may determine organoleptic characteristics and biological properties of the end-product. [ABSTRACT FROM AUTHOR]

Highlights: [•] Quinoa is a good source of saponins and phenolic compounds. [•] A pearling degree of 30% was necessary to obtain sweet quinoa. [•] Pearling process is a promising sustainable method to obtain sweet quinoa. [Copyright &y& Elsevier]

Abstract: The aim of this paper was to use the air classification technology to produce barley flours enriched in phenolic compounds and to obtain naturally enriched ingredients for pasta and bakery industry. Phenolic compounds in barley have been described in literature using different methodologies that are not easily comparable. This paper describes a comparative study between different separative and spectrophotometric methods to determine free and bound phenolic compounds in barley flours and their air classified fractions from three different cultivars grown in the same experimental field. To this end, reversed phase-high performance liquid chromatography, micellar electrokinetic chromatography, and spectrophotometric determinations were applied. The barley phenolic compounds analyzed included mainly catechins and proanthocyanidins as free phenols, and hydroxycinnamic acids and their derivatives as bound phenols. The enriched fractions obtained by air classification showed an increase of free flavan-3-ols of 157–173% compared to whole flour. The same fractions also reported larger concentration of bound phenolic compounds (160–236%) with respect to whole flours. Air classification results a good technique to enrich the flours and to utilize the barley co-products. [Copyright &y& Elsevier]

Keywords: food fermentation; food by-products; bioactive compounds; lactic acid bacteria; lycopene; phenolic compounds; biogenic amines; -aminobutyric acid (GABA) EN food fermentation food by-products bioactive compounds lactic acid bacteria lycopene phenolic compounds biogenic amines -aminobutyric acid (GABA) 153 1 04/02/20 20200201 NES 200201 Food fermentation is one of the most ancient processes of food production that has historically been used to extend food shelf life and to enhance its organoleptic properties. Moreover, recent advances in fermentation are focused on food by-products; in fact, they are a source of potentially bioactive compounds that, after fermentation, could be used as ingredients for nutraceuticals and functional food formulations [[1]]. This Special Issue aimed to present current knowledge and research trends concerning the use of fermentation technologies like the sustainable GRAS (Generally Recognized As Safe) process for food and nutraceutical production, to improve food quality. [Extracted from the article]

Abstract: The phenolic compounds present in seven samples of olive fruits were analysed by a rapid and resolutive LC–ESI-TOF MS method. All samples were collected during the normal picking period for olive oil production, in central and south Tunisia, and were obtained from the Oueslati variety cultivated in different olive growing areas. In the Tunisian samples, 22 compounds have been characterised by LC–ESI-TOF MS analysis. Results showed no qualitative differences in the phenolic fractions between virgin olive oils from different geographical region. However, significant quantitative differences were observed in a wide number of phenolic compounds. These results permit to use the phenolic fractions as an indicator of each region. [Copyright &y& Elsevier]

• Addition of polyphenols can mitigate the acrylamide formation in fried potato model. • The added polyphenols are obtained from the olive oil supply chain. • Hydrophobicity and activity of the polyphenols seem to be correlated. • TyAc and HTyAc presented the highest mitigation effects on AA content. • TyAc added to the dough showed around 90 % AA reduction. In order to find innovative protocols to reduce acrylamide (AA), a genotoxin and a probable carcinogen, in foods, several phenolic compounds were considered as additives to a potato derivative. Phenols are obtained from the by-products of the olive production chain. Potato flakes were kneaded with water containing different concentrations of a single phenol: tyrosol (Ty), hydroxytyrosol (HTy), tyrosyl acetate (TyAc), hydroxytyrosyl acetate (HTyAc), caffeic acid and oleuropein. After a cooking step at 175 °C for 4 min, AA was extracted, derivatized with xanthydrol and quantified by GC–MS. The results obtained for Ty, HTy, caffeic acid and oleuropein showed AA reduction ranging from 29 % to 47 %, whereas with TyAc and HTyAc the mitigation effect was noticeably stronger (90 and 75 %). The less polar molecule, TyAc, showed the best inhibition performance. These preliminary results show that phenolic compounds from olive by-products could also be valorized as food starchy additives. [ABSTRACT FROM AUTHOR]