Enantiomeric differentiation of three key volatile compounds in three different palm wines (Elaeis guineensis, Borassus flabellifer and Nypa fruticans)

The contents and enantiomeric distributions of three chiral compounds, linalool, phenylethanol and acetoin, were investigated in three different palm wines (i.e. Elaeis guineensis, Borassus flabellifer, and Nypa fruticans). While N. fruticans and B. flabellifer wines were predominated with the (S)-enantiomers of linalool, phenylethanol and acetoin, respectively, E. guineensis wine contained acetoin primarily as (R)-enantiomers in addition to the (S)-forms of linalool and phenylethanol. Interestingly, results revealed a high level of acetoin in all wines with concentrations ranging from 2437 to 6611 µg/L and an average ratio of S/R of 4:96–100:0. Moreover, noticeable differences occurred in the enantiomeric ratios and concentrations of enantiomers of the chiral compounds during storage. In all the wines, concentration of the (S)-form decreased during storage, whereas those of the (R)-form increased

Effect of processing and flavour fine-tuning techniques on the volatile flavour constituents of pseudocereals and some minor cereals

Different processing techniques have been used for many centuries to increase the amount of bioactive components and the subsequent fine-tuning of flavour compounds of pseudocereals and the lesser cereals. After an introduction into the different processing methods that leads to the formation of characteristic flavours in pseudocereal and the lesser cereal products, results of studies aimed at indicating the influence of biotechnical processes (e.g. germination and malting), sourdough/sourslurry fermentation and thermal processing on the final aroma of pseudocereal and the lesser cereal products are summarized in this review. Also, the characteristic flavour compounds in both the native and the products of the pseudocereals and the lesser cereals coupled with their stability are highlighted with respect to their contribution to the overall aroma

Effect of solid-state fermentation and drying methods on the physicochemical properties of flour of two plantain cultivars grown in Malaysia

The present work assessed the effect of solid-state fermentation (SSF) and drying methods [hot air drying (HAD) and hot air drying assisted by microwave finish drying (MFD)] on the physicochemical, functional and gelatinisation properties of flours of Nangka and Tanduk plantain cultivars. Drying methods and SSF did not affect the fat, dietary fibre and carbohydrate contents of the plantain flours. However, both treatments significantly affected the pH and titratable acidity of the flours. In addition, SSF coupled with MFD significantly increased the water absorption and oil absorption capacities of the flours more than the flours obtained from the hot air drying. Similar trend was observed with the swelling characteristics of the flours. Fermented and MFD flours had higher swelling power than flours obtained by hot air drying. Optical microscopy revealed that drying methods employed in the present work did not significantly alter the starch granules birefringence of the plantains

Effect of glycerol and stearic acid on the performance of chickpea starch-based coatings applied to fresh-cut papaya

This study examined the potential of incorporating stearic acid in starch-based edible coating formulations in order to increase the quality and shelf-life of fresh-cut papaya (“Sekaki” variety). Glycerol was employed as plasticizer and stearic acid was incorporated in proportions of; 0 %, 1%, 2%, and 3% (w/w). Film with 30% glycerol, 1% stearic acid, 5 g of starch, and 5% aloe Vera was chosen because it had low film solubility and water vapour permeability (29.54 ± 0.21, 2.99 ± 0.21), respectively. Furthermore, this film had slightly darker L* value (78.19 ± 1.21) which is an advantage because it will be able to reduce the loss of ascorbic acid (AA) which is sensitive to light and acceptable level of mechanical property The properties of the fresh-cut papayas were analysed during 12 days of storage at 10°C. The results obtained showed that the edible coating (i.e. film with 30% glycerol, 1% stearic acid, 5 g of starch, and 5% aloe Vera) significantly improved the physiochemical properties of fresh-cut papaya in terms of reduced weight loss, better firmness, better colour retention, and a slight decrease in AA content during storage. Furthermore, the microbial analysis showed that, the coating was able to extend the shelf life of fresh-cut papaya up to 12 days at refrigerated conditions

Classification of different pineapple varieties grown in Malaysia based on volatile fingerprinting and sensory analysis

Background: Pineapple is highly relished for its attractive sweet favour and it is widely consumed in both fresh and canned forms. Pineapple favour is a blend of a number of volatile and non-volatile compounds that are present in small amounts and in complex mixtures. The aroma compounds composition may be used for purposes of quality control as well as for authentication and classifcation of pineapple varieties. Results: The key volatile compounds and aroma profle of six pineapple varieties grown in Malaysia were investigated by gas chromatography–olfactometry (GC-O), gas-chromatography–mass spectrometry and qualitative descriptive sensory analysis. A total of 59 compounds were determined by GC-O and aroma extract dilution analysis. Among these compounds, methyl-2-methylbutanoate, methyl hexanoate, methyl-3-(methylthiol)-propanoate, methyl octanoate, 2,5-dimethyl-4-methoxy-3(2H)-furanone, δ-octalactone, 2-methoxy-4-vinyl phenol, and δ-undecalactone contributed greatly to the aroma quality of the pineapple varieties, due to their high favour dilution factor. The aroma of the pineapples was described by seven sensory terms as sweet, foral, fruity, fresh, green, woody and apple-like. Conclusion: Inter-relationship between the aroma-active compounds and the pineapples revealed that ‘Moris’ and ‘MD2’ covaried majorly with the fruity esters, and the other varieties correlated with lesser numbers of the fruity esters. Hierarchical cluster analysis (HCA) was used to establish similarities among the pineapples and the results revealed three main groups of pineapples

Effect of chitosan and carrageenan-based edible coatings on post-harvested longan (Dimocarpus longan) fruits

The effect of chitosan/carrageenan and glycerol as edible coating materials in preserving the fresh longan fruits stored at ambient temperature was evaluated. The concentration of coating components played an important role in the process of controlling quality changes and quantity losses. Changes in fruits’ weight loss, respiration rate and color were used as a measure of the coating’s effectiveness. Results have shown that increase in the chitosan or carrageenan concentration led to significant (p 1.19%) of the carrageenan resulted in slight increases in water and weight losses. From the multiple response optimization analysis, a combination of 1.29% (w/v) chitosan with 0.42% glycerol and 1.49% (w/v) carrageenan with 0.03% glycerol were predicted to give the desired coating because they were able to preserve the longan by showing minimal quality changes and quantity losses

Identification of the aroma compounds in Vitex doniana sweet: free and bound odorants

Background: Most often, the glycosidically-bound aroma compounds are released during industrial processing or pre-treatment of fruits. This usually introduces modification to the aroma notes of such fruits. Therefore, there isthe need to understand the contribution of these bound aroma compounds to the overall aroma of a given fruit. In recent years research studies have reported on the free- and bound volatile compounds of several fruits. However, there is no report yet on Vitex doniana sweet. Results: Results of gas chromatography–mass spectrometry (GC–MS) and gas chromatography–olfactometry (GC–O) of free and glycosidically-bound aroma-active compounds from Vitex doniana sweet revealed a total of 35 compounds in the free fraction, and 28 compounds were in the bound fraction respectively. Whilst the major group of compounds in the free fraction were terpenes, alcohols, and esters, the bound fraction consisted of ketones, alcohols, terpenes and norisoprenoids. Conclusion: A comparative analysis of the aroma potencies of the free and bound volatile fractions revealed that; free fraction exhibited strong potency for the fruity and floral notes, and the bound fraction produced more of the flowery, caramel-like and cherry-like notes. In addition results of odour activity values showed that ethylbutanoate, β-damascenone, ethyl-2-methyl propionate, linalool, hexyl acetate and (Z)-rose oxide contributed highly to the sweet prune-like aroma of the fruit