Impact of Japanese beetles (Popillia japonica Newman) on the chemical composition of two grape varieties (Nebbiolo and Erbaluce) grown in Italy

The effect of Japanese beetles (P. japonica) on critical quality indicators of Nebbiolo and Erbaluce grapes, specifically on their phenolic and volatile composition, was assessed. Adult beetle symptoms include extended skeletonization of leaves. Leaves are frequently left with their mid-vein intact but, when severely damaged, quickly turn brown. However, the plant tends to recover by generating a new leaf apparatus and the grapes reach ripeness. It emerged that the phenolic content of grapes produced by plants attacked by P. japonica (396 and 550 mg/kg, Nebbiolo and Erbaluce respectively) was generally higher when compared to healthy plants (266 and 188 mg/kg, Nebbiolo and Erbaluce respectively). Similarly, in the (red) Nebbiolo cultivar, the anthocyanin content was significantly lower in grapes produced with healthy plants. The influence of P. japonica on the volatile composition of Nebbiolo and Erbaluce grapes showed a total volatile fraction of affected grapes (433 and 439 µg/kg, respectively) significantly higher than the one related to healthy grapes (391 and 386 µg/kg, respectively). In response to the attack by P. japonica the plant significantly increases the content of some volatile compounds such as hexanal, (E)-2-hexenal, 1-hexanol, (E)-2-hexen-1-ol and phenyl ethyl alcohol.

Grape seed oil volatiles and odour activity values: a comparison with Turkish and Italian cultivars and extraction methods

Valorization of bioactive-rich wastes of food industry, such as grape seeds, is one of the most popular topic worldwide. The present study is designed to examine the volatiles of grape seed oils obtained by two Turkish (cvs. Okuzgozu and Emir) and two Italian (cvs. Sangiovese and Moscatello) cultivars by using two well-known oil extraction methods, cold percolation (CP) and soxhlet (SX). In order to evaluate their volatile composition, obtained oil extracts were subjected to purge and trap aroma extraction chamber combined with gas chromatography-mass spectrometry GC-MS. Revealed results showed that the oil yield, volatile compositions and odor activity values (OAVs) of grape seed oils altered depending on both variety and extraction method of the oil. According to results, a total of 60 and 67 volatile compound were detected in CP and SX aromatic extracts. High temperature applied during SX led to form new volatiles and increase in overall volatile composition due to oxidation reactions. Among all aroma groups, alcohols were the dominating aroma group followed by esters in each cultivar for both extraction methods. GSOs obtained by red grape varieties exhibited apparently higher ester concentration while white varieties were abundant in terpenes. Additionally, SX method caused to form some heat derived volatiles. Moreover, a total of 26 and 33 aroma compounds possessed OAVs greater than 1 and ethyl octanoate (sweet-apple odour), nonanal (fatty-citrus odour) and 1-octen-3-ol (mushroom, earthy odour) were found to be dominant volatiles with respect to their OAVs.

Impacts of novel blanching treatments combined with commercial drying methods on the physicochemical properties of Irish brown seaweed Alaria esculenta

Alaria esculenta is one of the most abundant edible brown seaweeds in Irelandandisconsidered an excellent source of nutrients, sought after by the food, nutraceutical and pharmaceutical industries. Seaweed is typically blanched and dried prior to consumption to enhance the end-product quality attributes and shelf life. Three blanching techniques were examined in this work; conventional hot water blanching, novel ultrasound blanching and microwave blanching. The L* and b*colour metrics were affected significantly (P < 0.01) by the processing methods. There were 76 volatile compounds detected in blanched and dehydrated Alaria esculenta. Freeze-dried samples after treatment with microwave alone (at 1000 W) and microwave (800 W) combined with ultrasound (at 50% amplitude) had the highest retention rate of volatile compounds (up to 98.61%). Regarding mineral content, drying methods significantly affected (P < 0.05) the content of Ca, Co, Cu and Fe, while blanching treatments significantly affected (P < 0.05) the content of Na, Cu, Fe and Mn.

Impacts of selected lactic acid bacteria strains on the aroma and bioactive compositions of fermented gilaburu (Viburnum opulus) juices

Gilaburu fruit and its products have gained popularity due to their nutritional content, taste and health benefits. Even though fermented gilaburu juice is widely preferred and consumed in some regions, there is no detailed study on the optimization of the production conditions of this popular beverage. In this study, gilaburu fruit juices fermented naturally (NFJ) and with three commercial lactic acid bacteria (LAB) (L. plantarum: FJLP, L. delbureckii: FJLD, L. caseii: FJLC) were examined for the first time. The microbial properties, phenolics, aroma compounds, minerals, amino acid contents and sensory properties were examined. It was found that the phenolics and volatiles were richer in the samples fermented with LAB but their amino acid contents were in lower amounts as compared to the NFJ sample. The juices produced with L. plantarum (FJLP) and L. delbrueckii (FJLD) presented better aroma, colour, flavour, and overall acceptability.

Variations in the key aroma and phenolic compounds of champignon (Agaricus bisporus) and oyster (Pleurotus ostreatus) mushrooms after two cooking treatments as elucidated by GC-MS-O and LC-DAD-ESI-MS/MS

Volatiles, key odorants, phenolics and antioxidant properties of raw, boiled and oven-cooked champignon and oyster mushrooms were investigated. Total concentration of the volatiles was drastically reduced by both cooking treatments and the lowest contents were found in the oven-cooked sample. Alcohols and terpenes were the dominant aroma groups in the raw champignon and oyster sample, respectively. The highest FD factor (FD = 2048) was found for 1-octen-3-one and methional in raw and boiled champignon samples while the same FD factor was determined in 1-octen-3-ol and methional in raw and boiled oyster samples. It was determined that the phenolics were more abundant in champignon samples than the oyster samples and that the boiling process caused a decrease while oven-cooking resulted in an increase in the amount of phenolics in both varieties. It was revealed that cooking was a crucial factor for the key odorants and phenolics in champignon and oyster mushrooms.

Characterization of Aroma-Active Compounds in Seed Extract of Black Cumin (Nigella sativa L.) by Aroma Extract Dilution Analysis

Turkish Nigella sativa L. seed extracts were used to detect the aroma and key odorant compounds of the spice using gas chromatography-mass spectrometry-olfactometry (GC-MS-O). Volatile compounds were extracted by the purge and trap extraction (PTE) method. A total of 32 volatile compounds consisting of different chemical classes acids (13), alcohols (7), phenols (3), terpene (1), esters (2), ketones (2), aldehyde (1), lactone (1) and hydrocarbons (2) were determined. The amounts of volatile compounds were found to be 21,544 µg kg−1. The application of aroma extract dilution analysis (AEDA) revealed the presence of 13 odor-active compounds alcohols (2), carboxylic acids (4), phenols (2), terpene (1), ketone (1), hydrocarbon (1) and unknown compounds (2) in Nigella sativa L. extract. Flavor dilution (FD) factors of key odorants ranged between 4 and 1024, while odor activity values (OAV) were in the range of 1.0 to 170.8. Acetoin was the only aroma-active ketone detected in Nigella sativa L. seed extracts. It had the strongest aroma (FD = 1024) and provided a buttery odor. This compound represented the most abundant compound of overall aroma profile with a concentration of 9394 µg kg−1, followed by isobutanoic acid (FD = 512 with a concentration of 218 µg kg−1) and contributed a powerful aroma and a cheesy characteristic odor.

Screening of key odorants and anthocyanin compounds of cv. Okuzgozu (Vitis vinifera L.) red wines with a free run and pressed pomace using GC-MS-Olfactometry and LC-MS-MS

The principal purpose of the present work is to characterize the aroma, aroma-active, and anthocyanin profiles of Okuzgozu wines and to observe the effect of the pomace pressing technique on these parameters. A total of 58 and 59 volatile compounds were identified and quantified in free-run juice wine (FRW) and pressed pomace wine (PW). Alcohols were found as the most dominant group among aroma compounds followed by esters and acids. However, among all these compounds, only 11 and 13 of them could be considered as key odorants in aromatic extracts of FRW and PW, respectively. According to GC-MS-O analysis, ethyl octanoate (fruity), phenyl ethyl acetate (fruity), and 2-phenyl ethanol (flowery) were found as the main contributors to the overall scent of both wines. Beyond the aroma profiles, anthocyanin contents of both types of wines were also investigated, and total 14 and 15 anthocyanins were identified and quantified in FRW and PW. Malvidin-3-glycoside and its acetyl and coumaroyl forms were identified as the dominant anthocyanins in both wines. It is worth noting the pressing application (2.0 atm) led to an increase of some unpleasant notes in the aroma providing chemical, pharmacy, and fermented aromas in wine. On the other hand, the wines produced with pressed pomace presented higher amounts of anthocyanins.

Aroma compounds of non-alcoholic fermented beverage: Gilaburu juice

The present research was planned to characterize the aroma composition of Viburnum opulus L. which is one important members of the Caprifoliaceae family. Volatile components of Viburnum opulus L. were extracted by use of the purge and trap technique with dichloromethane and analyzed by gas chromatography-mass spectrometry (GC-MS). The extraction method gave highly representative aromatic extract of the studied sample. A total of 47 aroma compounds were found including acids, alcohols, ketones, volatile phenols, aldehydes, furans, lactones, an ester a terpene and a pyranone. Among all aroma compounds, isovaleric acid was found as the most abundant aroma compound in the fermented GR juice, having a 30% of total aroma concentration. Butanoic acid, 4-methyl catechol and propanoic acid were other aroma compounds found in higher concentrations (18%, 11% and 6% respectively).

Monitoring of compositional changes during berry ripening in grape seed extracts of cv. Sangiovese (Vitis vinifera L.)

BACKGROUND

Seed oil and flours have been attracting the interest of researchers and industry, since they contain various bioactive components. We monitored the effects of ripening on lipids, monomeric flavan-3-ols, proanthocyanidins and tocols concentration in seed extracts from organically cultivated cv. Sangiovese vines.

RESULTS

Linoleic acid was the most abundant fatty acid, followed by oleic, palmitic and stearic acids. The tocols detected were α-tocopherol, α-tocotrienol and γ-tocotrienol. The proanthocyanidins degree of polymerisation ranged from dimers to dodecamers; moreover, monomeric flavan-3-ols and polymeric proanthocyanidins were detected. Total flavan-3-ols (monomers, oligomers and polymers) concentration in grape seeds decreased during ripening.

CONCLUSIONS

Fatty acids reached the highest level in post-veraison. The concentration of these compounds varied considerably during ripening. Capric acid has been found for the first time in grape seeds. α-Tocopherol and γ-tocotrienol decreased during ripening, while α-tocotrienol increased. The HPLC analysis with fluorimetric detection, conducted for the first time on cv. Sangiovese, revealed that the concentration of flavan-3-ols monomers, oligomeric proanthocyanidins and polymers greatly changed during ripening. These results suggest that the timing of bunch harvest plays a crucial role in the valorisation of grape seed flour. © 2016 Society of Chemical Industry.