Defining the Sensory Profiles of Raw Almond ( Prunus dulcis) Varieties and the Contribution of Key Chemical Compounds and Physical Properties.

This study describes the sensory composition of commercial sweet almond varieties across two California growing seasons. It also discusses the relationship between sensory attributes and chemical and physical measures. Raw, whole almonds (43 samples each of 13 varieties in 2015 and 40 samples each of 10 varieties in 2016) were evaluated for their sensory profiles using descriptive sensory analysis. The 2016 samples were also analyzed for macro- and micronutrients, amygdalin, volatile composition (using gas chromatography-mass spectrometry), and physical properties, and the results were modeled with the sensory data. Independence, Sonora, and Wood Colony were harder, more fracturable, and crunchy, whereas Fritz and Monterey were more moist and chewy, reflecting their moisture contents. Aldrich and Fritz were higher in marzipan/benzaldehyde flavor, which is related to amygdalin, benzaldehyde, phenylethyl alcohol, and benzyl alcohol. New insights are provided into sweet-almond composition and the sensorial contribution of headspace volatiles. This assists almond growers and processors in describing and marketing almond varieties.

Flavor and Acceptance of Roasted California Almonds During Accelerated Storage.

Monitoring oxidative flavor changes in almonds is possible only if the chemical and sensory profile during roasting and storage is first established. Herein, almonds roasted at two different temperatures (115 and 152 °C) were stored at 39 °C for 0 to 12 months and were analyzed by headspace solid-phase microextraction gas chromatography-mass spectrometry, descriptive analysis, and consumer hedonic analysis. Volatile profiles, descriptive sensory profiles, and consumer hedonic scores were analyzed for predictive relationships. Descriptive attributes involving Roasted and Nutty as well as consumer liking were highest in fresh almonds, while flavors typically associated with oxidative rancidity such as Cardboard, Painty/Solvent, Soapy, and Total Oxidized increased during storage. Compounds most important for predicting rancidity-related attributes were lipid oxidation products, including pentanal, hexanal, heptanal, and octanal. Consumer liking was best predicted by similar compounds to those predicting Clean Nutty flavor, including Maillard reaction products such as 2- and 3-methylbutanal, 2-methylpyrazine, and 2,5-dimethylpyrazine.

Chemical and Sensory Characterization of Oxidative Changes in Roasted Almonds Undergoing Accelerated Shelf Life.

In almonds, there is no standard method for detecting oxidative changes and little data correlating consumer perception with chemical markers of rancidity. To address this, we measured peroxide values (PV), free fatty acid values (FFAs), conjugated dienes, tocopherols, headspace volatiles, and consumer hedonic response in light roasted (LR) and dark roasted (DR) almonds stored under conditions that promote rancidity development over 12 months. Results demonstrate that, although rancidity develops at different rates in LR and DR almonds, consumer liking was not significantly different between LR and DR almonds. Average hedonic ratings of almonds were found to fall below a designated acceptable score of 5 ("neither like nor dislike") by 6 months of storage. This did not correspond with recommended industry rejection standard of PV < 5 mequiv peroxide/kg oil and FFA < 1.5% oleic. FFAs remain well below <1.5% oleic during storage, indicating that FFAs are not a good marker of rancidity in roasted almonds stored in low humidity environments. Regression of consumer liking to concentration of rancidity indicators revealed that selected headspace volatiles, including heptanal, octanal, nonanal, 2-octenal, 2-heptanone, 2-pentylfuran, hexanal, and pentanal, had a better correlation with liking than did nonvolatile indicators.

Regional sensory and chemical characteristics of Malbec wines from Mendoza and California.

Malbec grapes are widely grown and studied in Argentina, whereas the smaller production in California is less well known. This study sought to define and compare Malbec wine compositions from various regions in Mendoza, Argentina and California, USA. The Malbec wines were clearly separated, based on their chemical and sensory profiles, by wine region and country. Descriptors of Malbec wines were aromas of cooked vegetal, earthy, soy and volatile acidity, as well as acidic taste and astringent mouthfeel, regardless of the region of origin. Malbec wines from Mendoza generally had more ripe fruit, sweetness, and higher alcohol levels, while the Californian Malbec wines had more artificial fruit and citrus aromas, and bitter taste. Compositional differences between the two countries were related more to altitude than precipitation and growing degree days. To our knowledge, this is the first time that an extensive regionality study has been attempted for Malbec wines.

Sensory profiles for dried fig (Ficus carica L.) cultivars commercially grown and processed in California.

A trained sensory panel evaluated the 6 fig cultivars currently sold in the California dried fig market. The main flavor and aroma attributes determined by the sensory panel were "caramel," "honey," "raisin," and "fig," with additional aroma attributes: "common date," "dried plum," and "molasses." Sensory differences were observed between dried fig cultivars. All figs were processed by 2 commercial handlers. Processing included potassium sorbate as a preservative and SO2 application as an antibrowning agent for white cultivars. As a consequence of SO2 use during processing, high sulfite residues affected the sensory profiles of the white dried fig cultivars. Significant differences between dried fig cultivars and sources demonstrate perceived differences between processing and storage methods. The panel-determined sensory lexicon can help with California fig marketing.

Describing the appearance and flavor profiles of fresh fig (Ficus carica L.) cultivars.

Twelve fig cultivars, including cultivars destined for the fresh and dried markets, were harvested from 6 locations and evaluated by a trained panel using descriptive sensory analysis. Instrumental measurements were taken at harvest and also during sensory analysis. Each fresh fig cultivar had a characteristic appearance and flavor sensory profile regardless of the source. The primary flavor attributes used to describe the fig cultivars were "fruity,""melon,""stone fruit,""berry,""citrus,""honey,""green," and "cucumber." Maturity levels significantly affected the chemical composition and sensory profiles of the fig cultivars. Less mature figs had a higher compression force, a thicker outer skin, and higher ratings for "green" and "latex" flavors, firmness, graininess, bitterness, tingling, and seed adhesiveness. Meanwhile, more mature figs had higher soluble solids concentration, and were perceptibly higher in "fruit" flavors, juiciness, stickiness, sliminess, and sweetness. The specific sensory terminology used for fig appearance and flavor profiles will assist with communication between marketers and consumers, which can increase fresh fig consumption.

The influence of yeast on the aroma of Sauvignon Blanc wine.

The main objective of this study was to investigate the effect of different Saccharomyces cerevisiae wine yeast strains on the concentration of aroma-enhancing volatile thiols and fermentation metabolites in Sauvignon Blanc wine. Seven commercial wine yeast strains were selected based on their putative ability to modulate the concentrations of the fruity volatile thiols, 4-mercapto-4-methylpentan-2-one (4MMP), 3-mercapto-hexanol (3MH) and 3-mercapto-hexylacetate (3MHA). Each of these yeasts was used to produce Sauvignon Blanc wines under controlled conditions, in triplicate, in 20-L quantities. The levels of 4MMP, 3MH and 3MHA in these wines were quantified using the p-hydroxymercuribenzoate method. In addition, a total of 24 volatile yeast-derived fermentation aroma compounds were also quantified using headspace solid-phase microextraction coupled with gas chromatography mass spectrometry (HS-SPME-GC-MS). Formal sensory analysis was conducted by 12 trained assessors and, additionally, a panel of 24 experienced wine industry professionals assessed the wines and ranked them in order of preference. The results indicated that the yeast strains varied significantly in terms of their capabilities to (i) produce volatile thiols and fermentation metabolites; and (ii) to modulate the varietal characters of Sauvignon Blanc wine. Yeast strains that produced the highest levels of volatile thiols were responsible for wines with the highest perceived intensity of fruitiness, and these wines were preferred by the tasting panels. While the 'green' characters in Sauvignon Blanc wines can be manipulated through vineyard management, the 'tropical fruity' characters appear to be largely dependent on the wine yeast strain used during fermentation. Therefore, the choice of yeast strain offers great potential to modulate wine aroma profiles to definable styles and predetermined consumer market specifications.

Coinoculated fermentations using saccharomyces yeasts affect the volatile composition and sensory properties of Vitis vinifera L. cv. sauvignon blanc wines.

Alcoholic fermentation using Saccharomyces wine yeast is an effective means of modulating wine aroma. This study investigated the impact of coinoculating commercial yeast strains (Vin7, QA23, Vin13) on the volatile composition and sensory profile of Sauvignon Blanc wines. Small-scale replicated fermentations were conducted using single-strain and coinoculations of Vin7 with QA23 and with Vin13. The results showed that the chemical and sensory profiles of the coinoculated wines were different from both the single-strain wines and equal blends of the single-strain wines. Volatile thiol analysis indicated that the Vin7/QA23 coinoculated wines were highest in 3-mercaptohexan-1-ol (3MH) and 3-mercaptohexyl acetate (3MHA), although this pattern was not observed for the Vin7/Vin13 yeast combination. The negative white vinegar aroma and high volatile acidity measured in the Vin7 single-strain wines were not present in the coinoculated wines. This study demonstrates that coinoculations can modify the aroma profile of wines, when complementary yeasts are used.