Aroma of minor tropical fruits

Chemical and nutritional characterization of Ambelania duckei (Apocynaceae) an unexplored fruit from the Amazon region

Ambelania duckei Markgr is a species of the Apocynaceae family, native to the Amazon region that is unexplored from a nutritional point of view and studied in relation to its chemical constituents. This work presents an unprecedented study of the proximate composition, lipid profile, a chromatographic analysis, and the antioxidant activity of extracts obtained from the pulp, peel and seeds of the fruit. The results showed that potassium, calcium, and magnesium stood out as the most abundant key minerals in the fruit peel and pulp, with an emphasis on the potassium present in the fruit pulp at 1750.0 mg/100 g. The peel had the highest content of total phenolics (374.86 mg/g), flavonoids (15.54 mg/g), tannins (27.45 mg/g) and O-diphenols (379.36 mg/g; 645.71 mg/g). The antioxidant activity (AA) was highest in the peel compared to the pulp in the DPPH, ABTS, and ORAC tests showing: IC₅₀ of 29.82; 43.67; and 407.13 µg/mL, respectively but a lower activity for the Fe²⁺ chelator. The analysis of the lipid fractions from the peel, pulp, and seeds of the A. duckei fruit resulted in 14 types of fatty acids. The major fatty acids found in the three parts of the fruit were oleic acid (peel, 22.52 %), palmitic acid (pulp, 17.34 %), and linoleic acid (seeds, 47.99 %). The lipid profile and nutritional aspects had a PUFA/SFA ratio (0.4-1.8) in the different parts of the A. duckei fruit; the atherogenic and thrombogenic indexes were higher in the peel (1.23) and pulp (0.62), respectively. The ratio between the hypocholesterolemic and hypercholesterolemic fatty acids (0.5 - 3.8) calculated for the fruit are within the desirable range for a nutritious food. The chromatographic analysis of the volatile organic compounds (VOCs) from the peel and pulp of the fruit, identified 74 VOCs, of which 60.9 % are related to terpenes, and emit notes such as cucumber, green, fatty, floral, and mint, due to the presence of substances with OAVs > 10, especially α-ionone, 1,8-cineole, 2,4-decadienal, and dodecanal. The analysis of the MS and MS/MS spectra of the chromatograms obtained by LC- QTOF-HRMS led to the identification of 26 compounds in the peel, seeds and pulp of A. duckei, such as fatty acids, phenolic acid, flavonoids, proanthocyanidins, alkaloids, and terpenoids. The results show that the pulp of A. duckei has potential as nourishing food and the nutritional and chemical aspects of the peel can be applied to commercial applications.

Qualitative identification of volatile compounds in foods and flowers using passive headspace extraction with activated charcoal fabric

This study investigates the application of passive headspace analysis to several different foods and flowers and compares these results to other published studies. The method demonstrates the applicability of passive headspace analysis for extraction and qualitative analysis of volatile flavor components of citrus fruits and flower blossoms. The method is simple, inexpensive, fast, and provides an alternative to analysis of volatile flavor and fragrance compounds using solid phase microextraction techniques and other extraction techniques.

Microbial Production of Value-added Products from Cashew Apples- an Economical Boost to Cashew Farmers

Cashew farming-considered as one of the major profit-making agricultural businesses-requires renewed practices in processing its products and by-products for sustained growth. The current review highlights the commercial potential of cashew apples by proposing value-addition strategies through microbial fermentation routes that can help garnering additional profit to the growers. The immense potential of cashew apples and pulp wastes generated after juice-extraction in producing a range of products through the fermentation process such as bioethanol, hydrolytic enzymes, lactic acid, biosurfactants, wine and Feni (an alcoholic beverage) is discussed. Furthermore, a case on the existing Feni-making practices in Goa, India is reviewed, and the need for upgrades in the processing methods for waste mitigation is emphasized. Based on the literature survey and from the gathered knowledge on cashew industries through visits to various cashew farming sites, it is strongly emphasized that a radical improvement in cashew farming is possible only through the adoption of holistic approaches in the cultivation and proper utilization of wastes and its management of cashew apples. Also, Feni production, which is the mainstay of India’s current cashew processing industry, requires major up-gradation in processing methods to improve its quality, marketability, and export potential.

Vinegar production from <i>Theobroma grandiflorum</i> SCHUM (cupuassu)

<abstract> <p>The tropical fruit cupuassu comes from <italic>Theobroma grandiflorum</italic> (SCHUM), a close relative of cocoa. Cupuassu has a rich yet delicate flavour profile with notes of chocolate, pineapple, passion fruit and other fruits. Here, we produced a cupuassu-fruit wine using a <italic>Saccharomyces cerevisiae</italic> inoculum (and univariate analysis to determine conditions for optimum ethanol production) and then fermented this wine to produce a delicate and unique cupuassu vinegar using acid-acid bacteria. The cupuassu wine was produced by fermentation of juice chaptalized with sucrose, with a final ethanol concentration of 10% (v/v). Acetic-acid fermentations were carried out in both a bubble-column reactor and a mechanically non-aerated reactor (high-surface reactor), producing final concentrations of 4.5 and 3.3% (w/v) acetic acid, respectively. The ethanol- and acetic-acid yields obtained were comparable to those of other fruit wines and fruit vinegars. The cupuassu vinegar retained the rich flavor profile of the cupuassu. We believe that the production of flavorsome products from local plants can have benefits for conservation by promoting ecologically sustainable agriculture and may contribute to cultural identity of Amazon people.</p> </abstract>

Volatile compounds associated to the loss of astringency in 'Rama Forte' persimmon fruit

The volatile profile of 'Rama Forte' persimmon fruit treated with high concentration of CO₂ or ethanol, as well as the association of specific volatile organic compounds (VOC) to the loss of astringency given by sensory and chemical evaluation were investigated in our study. Fruit were harvested at the maturity stage showing crisp texture and commercial color, and exposed to different astringency removal treatments: 70% CO₂ for 18 h or 1.70 mL kg^-1 ethanol for 6 h. Fruit were daily assessed for VOC, astringency, and soluble tannins content throughout eight days at room temperature. The HS-SPME/GC-MS analysis allowed to tentatively identify 31 volatile compounds and two fatty acids. A clear separation of the persimmon fruit from the beginning to the end of the post-treatment period was showed by PCA results, mainly from the fifth day for CO₂-treated and the seventh day for ethanol-treated persimmon. The loadings from CO₂ treatment highlighted the increase in the concentrations of a great number of compounds with the progression of the days. The compounds 2,4-di-tert-butylphenol and 1-pentadecanal were tentatively identified on fruit from both treatments after the longest periods and were absent on astringent non-treated fruit. These compounds are reported for the first time on persimmon fruit. Astringency tending to absent was noticed from the fifth and the seventh day after the fruit exposition to CO₂ and ethanol vapor, respectively, when flesh soluble tannins concentrations close to 0.1% FW were found. Our study indicates a strong relationship between the astringency removal and the compounds 2,4-di-tert-butylphenol and 1-pentadecanal, supporting them as potential marker compounds for artificial deastringency in 'Rama Forte' persimmon fruit.

Volatile biomarkers for early-stage detection of insect-infested brown rice: Isopentenols and polysulfides

To reduce food loss from stored products by insect attack, monitoring and early detection of insects are essential. Presently, monitoring with pheromone traps is the primary method for detection; however, traps are effective only after the insects propagate. Detection and identification of the early volatile biomarkers arising from insect-infested brown rice was performed in this study to develop an alternative detection strategy. Brown rice was infested with eggs of seven insect species, including Sitophilus zeamais and Plodia interpunctella. Infested rice emitted at least one of the volatile compounds prenol, isoprenol, dimethyl disulfide, and dimethyl trisulfide (DMTS). In particular, isopentenols were generated by moths within one week of infestation, whereas they were not released from non-infested rice. DMTS was detected from all insect-infested brown rice, especially S. zeamais and P. interpunctella. These volatiles are potential early biomarkers for the presence of insects in brown rice.

Evaluation of Amazon fruits: chemical and nutritional studies on Borojoa sorbilis

BACKGROUND

Borojoa sorbilis (Ducke) is an Amazonian species with edible fruits that are widely consumed by the local population, but little studied and not yet economically explored. Thus the aim of this study was to describe the chemical composition, volatile compounds, nutritional aspects and antioxidant activity of the fruit pulp and peel of B. sorbilis.

RESULTS

Headspace solid-phase microextraction, using polydimethylsiloxane-divinylbenzene (PDMS-DVB) fiber, resulted in the identification of 59 substances in the pulp and peel of B. sorbilis fruits after analysis of the chromatograms obtained by gas chromatography-mass spectrometry using polar and nonpolar columns. Esters were the most abundant. Moisture, lipids, protein, dietary fiber, ash, carbohydrate, total energy value, titratable acid, soluble solids and pH were measured. Protein amount, fat content and antioxidant activity were low in both pulp and peel. Carbohydrate content was 179.2 and 134.9 g kg^-1 in pulp and peel, respectively.

CONCLUSION

This is the first report on the chemical characteristics, flavor and nutritional aspects of B. sorbilis fruit, which is essential to its economic exploitation. The high energy value associated with the carbohydrate content, plus the low fat content, contribute to a possible use of B. sorbilis fruits as a food supplement. © 2018 Society of Chemical Industry.

Flavor characterization of native Peruvian chili peppers through integrated aroma fingerprinting and pungency profiling

A broad range of Peruvian chili peppers are available but not properly characterized. To increase the insight into their flavor compounds, a head space GC-MS fingerprinting (volatiles) and an HPLC-based profiling approach (pungency) was implemented to characterize twenty landraces (Capsicum annuum, C. baccatum and C. chinense). The data obtained was analyzed with powerful chemometric approaches to identify unique flavor compounds for each of the species and for each of the landraces within a specific species. The pungency profile and volatiles such as esters, terpenes and norcarotenoids distinguish Cerezo triangular (4) (C. annuum). Mainly esters provoked the separation between Chico (42), Cacho de cabra rojo (323), Amarillo de Chachapoyas (318) (C. baccatum), Arnaucho (60) and Miscucho amarillo (69) (C. chinense). This study demonstrates the potential of the integrated fingerprinting, profiling and a chemometric approach to extensively understand the unique flavor compounds in Peruvian chili peppers.

Comparison of techniques for the isolation of volatiles from cashew apple juice

BACKGROUND

The aim of this study was to compare the performance of the following techniques on the isolation of volatiles of importance for the aroma/flavor of fresh cashew apple juice: dynamic headspace analysis using PorapakQ(®) as trap, solvent extraction with and without further concentration of the isolate, and solid-phase microextraction (fiber DVB/CAR/PDMS).

RESULTS

A total of 181 compounds were identified, from which 44 were esters, 20 terpenes, 19 alcohols, 17 hydrocarbons, 15 ketones, 14 aldehydes, among others. Sensory evaluation of the gas chromatography effluents revealed esters (n = 24) and terpenes (n = 10) as the most important aroma compounds.

CONCLUSION

The four techniques were efficient in isolating esters, a chemical class of high impact in the cashew aroma/flavor. However, the dynamic headspace methodology produced an isolate in which the analytes were in greater concentration, which facilitates their identification (gas chromatography-mass spectrometry) and sensory evaluation in the chromatographic effluents. Solvent extraction (dichloromethane) without further concentration of the isolate was the most efficient methodology for the isolation of terpenes. Because these two techniques also isolated in greater concentration the volatiles from other chemical classes important to the cashew aroma, such as aldehydes and alcohols, they were considered the most advantageous for the study of cashew aroma/flavor.

Effects of propylene glycol alginate and sucrose esters on the physicochemical properties of modified starch-stabilized beverage emulsions

This study was conducted to investigate the effect of main emulsion components namely, modified starch, propylene glycol alginate (PGA), sucrose laurate and sucrose stearate on creaming index, cloudiness, average droplet size and conductivity of soursop beverage emulsions. Generally, the use of different emulsifiers or a mixture of emulsifiers has a significant (p < 0.05) effect on the response variables studied. The addition of PGA had a significant (p < 0.05) effect on the creaming index at 55 °C, while PGA-stabilized (PGA1) emulsions showed low creaming stability at both 25 °C and 55 °C. Conversely, the utilization of PGA either as a mixture or sole emulsifier, showed significantly (p < 0.05) higher cloudiness, as larger average droplet size will affect the refractive index of the oil and aqueous phases. Additionally, the cloudiness was directly proportional to the mean droplet size of the dispersed phase. The inclusion of PGA into the formulation could have disrupted the properties of the interfacial film, thus resulting in larger droplet size. While unadsorbed ionized PGA could have contributed to higher conductivity of emulsions prepared at low pH. Generally, emulsions prepared using sucrose monoesters or as a mixture with modified starch emulsions have significantly (p < 0.05) lower creaming index and conductivity values, but higher cloudiness and average droplet size.

Volatile profile of cashews (Anacardium occidentale L.) from different geographical origins during roasting

Volatile compounds were quantified in the headspace of Indian, Vietnamese, and Brazilian cashews, both raw and during roasting by selected ion flow tube-mass spectrometry. The optimum roasting times based on color measurements were also determined. Raw cashews were oil roasted for 3 to 9 min at 143 °C and color and volatiles measured. An excellent correlation, following a pseudo 1st-order reaction, was found between L* value and roasting time; darkness increases as roasting time increases. The optimum roasting time was 6, 8, and 9 min for Vietnamese, Indian, and Brazilian cashews, respectively. Raw cashews had lower concentrations of volatiles than roasted cashews. Most volatiles significantly increased in concentration during roasting of Brazilian, Indian, and Vietnamese cashews. Only a few volatiles significantly decreased during roasting. Ethanol and 1-heptene significantly decreased during roasting in Brazilian cashews and toluene decreased in Vietnamese cashews. Brazilian cashews had significantly higher levels of most volatiles than Indian and Vietnamese cashews. Most volatile levels in Indian and Vietnamese cashews were not significantly different. Of the volatiles, Strecker aldehydes, including methylbutanal, 2-methylpropanal, and acetaldehyde, were at the highest concentration in roasted cashews. The Maillard reaction contributed to the formation of most of the volatiles in cashews from the 3 countries. There was also degradation of sugars to form furan-type compounds and oxidation of lipids to form alkanals such as hexanal.

PRACTICAL APPLICATION

The volatile profile during roasting of cashews can be used to determine the best roasting time for each type of cashew. The rate of color development and the production of volatiles differ for the cashews from the 3 geographical locations.

Gas chromatography-olfactometry in food flavour analysis

The application of gas chromatography-olfactometry (GC-O) in food flavour analysis represents to be a valuable technique to characterise odour-active, as well as character impact compounds, responsible for the characterizing odour of a food sample. The present article briefly reviews the use of GC-O in the flavour investigation of dairy products (milk and cheese), coffee, meat and fruits. Particular attention has been devoted to extraction techniques, GC-O hardware commonly utilised and olfactometric assessment methods, which can be applied to food analysis.