Neil C. Da Costa

Volatile Compounds and Sensory Analysis of Both Harvests of Double-Cut Yakima Peppermint (Mentha piperita L.)

North American peppermint oils are widely regarded as some of the most superior peppermint oils commercially available. Amongst them is Yakima double-cut peppermint oil (Mentha piperita L.). It has an aroma described as strong, refreshing, minty, slightly creamy, and very herbaceous with some of the most desirable flavor notes among peppermint oils. The peppermint is grown in the Yakima Valley of Washington State, USA. As one of the most northerly grown peppermints with longer days, it is unique as there are 2 harvests of the mint leaves in one season. For this study, samples of fresh and dried (hay) leaves were collected from both harvests; 1st cut, July and 2nd cut, September. Steam-distilled oils were produced from each harvest and analyzed by gas chromatography-mass spectrometry to give detailed profiles. The aroma and taste sensory attributes of each oil were evaluated. In addition, menthyl formate has previously been reported only once in the literature, but not as definitively as required by current flavor-regulatory bodies for use as a natural flavoring ingredient. It was conclusively reported in these peppermint oils.

The analysis of volatiles in Tahitian vanilla (Vanilla tahitensis) including novel compounds

Abstract Tahitian vanilla was analysed as part of IFFs ongoing Generessence® programme. This programme involves the in-depth analysis of a natural product to ultimately produce a new truly nature identical flavour and to discover new flavour molecules. Selected Tahitian vanilla beans were imported from French Polynesia and extracted by percolation. The ethanolic extract underwent further liquid/liquid extraction, and sampling by a sorptive stir bar. The volatiles of the beans were analysed by dynamic headspace and GC-MS. A total of 276 components were identified through these 3 analyses. Amongst them were novel compounds not previously reported in Tahitian vanilla [1]. These novel compounds were either purchased or synthesised for confirmation. The major semi-volatiles were analysed by HPLC. In addition the novel compounds were evaluated by an expert panel.

2,5-diketopiperazines in food and beverages: Taste and bioactivity

ABSTRACT 2,5-Diketopiperazines (2,5-DKPs) have been found to occur in a wide range of food and beverages, and display an array of chemesthetic effects (bitter, astringent, metallic, and umami) that can contribute to the taste of a variety of foods. These smallest cyclic peptides also occur as natural products and have been found to display a variety of bioactivities from antibacterial, antifungal, to anthroprotective effects and have the potential to be used in the development of new functional foods. An overview of the synthesis of these small chiral molecules and their molecular properties is presented. The occurrence, taste, and bioactivity of all simple naturally occurring 2,5-DKPs to date have been reviewed and those found in food from yeasts, fungi, and bacteria that have been used in food preparation or contamination, as well as metabolites of sweeteners and antibiotics added to food are also reviewed.

Identification, Synthesis, and Characterization of Novel Sulfur-Containing Volatile Compounds from the In-Depth Analysis of Lisbon Lemon Peels (Citrus limon L. Burm. f. cv. Lisbon)

Lemons (Citrus limon) are a desirable citrus fruit grown and used globally in a wide range of applications. The main constituents of this sour-tasting fruit have been well quantitated and characterized. However, additional research is still necessary to better understand the trace volatile compounds that may contribute to the overall aroma of the fruit. In this study, Lisbon lemons (C. limon L. Burm. f. cv. Lisbon) were purchased from a grove in California, USA, and extracted by liquid-liquid extraction. Fractionation and multidimensional gas chromatography-mass spectrometry were utilized to separate, focus, and enhance unidentified compounds. In addition, these methods were employed to more accurately assign flavor dilution factors by aroma extract dilution analysis. Numerous compounds were identified for the first time in lemons, including a series of branched aliphatic aldehydes and several novel sulfur-containing structures. Rarely reported in citrus peels, sulfur compounds are known to contribute significantly to the aroma profile of the fruit and were found to be aroma-active in this particular study on lemons. This paper discusses the identification, synthesis, and organoleptic properties of these novel volatile sulfur compounds.

Identification of Thiols in Yellow Onion (Allium cepa L.) Using Solvent Vented Large Volume Injection GC‐MS

Thiols are often highly odor active molecules and as such can significantly contribute to aroma while being present at extremely low concentrations. This paper details the identification of thiols in yellow onion juice by solvent extraction followed by thiol enrichment using a mercuric agarose gel column. Due to the inherent thermal instability and low concentrations of thiols in onion, chromatographic analysis utilized larger volume solvent elimination injections. New sulfur compounds in onion included 1,1-propanedithiol, bis-(1-sulfanylpropyl)-sulfide, 1-methylsulfanyl-1-propanethiol, 1-propylsulfanyl-1-propanethiol, and 1-allylsulfanyl-1-propanethiol. A discussion on the potential route of formation for each compound is included along with the orthonasal and retronasal evaluations of the synthesized molecules. This work investigated and identified 5 newly identified compounds present in onions that can impart onion character at low concentrations levels.