Michele R. Warmund

Volatile Compounds in Light, Medium, and Dark Black Walnut and Their Influence on the Sensory Aromatic Profile

UNLABELLED Light, medium, and dark colored kernels from 3 different cultivars (Emma K, Kwik Krop, and Sparks 127) and one wild species of black walnut were studied for their aroma volatiles. Solid-phase microextraction-gas chromatography-mass spectrometry was used to determine the aromatic compounds present in the headspace of these samples. Partial least square regression was used to correlate the instrumental aromatic data with the sensory responses, obtained in a previous study, for the same samples. Thirty-four aromatic compounds were found in the black walnut cultivars, highlighting among them the presence of 14 esters. Although more than 50% of the total concentration of volatile compounds, esters were not important compounds in determining the differences in the sensory aromatic profiles of the 3 colors of the nuts. As a general trend, the concentration of total volatile compounds was always significantly higher in light black walnuts than in the medium colored samples; medium colored samples had higher volatile content than the dark black walnuts. The presence of hexanal was related to rancid and acrid aromas and was determined to differentiate the dark black walnuts from the medium and light colored samples. PRACTICAL APPLICATION The data presented in this article will help understand the aromatic differences between light, medium, and dark colored kernels of domestic and wild black walnut. The aromatic profile of these nuts, not studied until this moment, can be used as a model to develop flavorings and new products by the food industries.

Descriptive sensory analysis and free sugar contents of chestnut cultivars grown in North America

BACKGROUND Various chestnut (Castanea) species and cultivars are currently produced and marketed in North America including Peach, Qing, AU-Homestead, Eaton, Marrone di Castel del Rio, and Colossal. In spite of their availability in the marketplace, similarities in sensory characteristics of chestnuts, as well as their unique attributes, have not been explored. Therefore, the objectives of this study were to evaluate texture and flavor attributes of commonly grown chestnut cultivars using descriptive sensory analysis and to quantify their free sugar content by gas-liquid chromatography. RESULTS Twenty-three sensory terms were used for descriptive analysis of roasted chestnuts. All but two attributes (raw impression and fermented) were common to all chestnut cultivars. Peelability, initial firmness, dissolvability, and mustard, sweet, and sour flavors varied among cultivars. Sucrose, the predominant free sugar in chestnuts, was greatest in Colossal chestnuts from California, while those of Peach had the lowest content. Glucose, fructose and maltose were also present in chestnuts. CONCLUSION This study demonstrated that cultivars of various chestnut species share several common sensory attributes, but differ in intensity ratings of six descriptors. Of these attributes, sweetness has been associated with consumer acceptance and can be promoted in the marketplace.

Morphometric analysis of young petiole galls on the narrow-leaf cottonwood, Populus angustifolia, by the sugarbeet root aphid, Pemphigus betae

An insect-induced gall is a highly specialized structure resulting from atypical development of plant tissue induced by a reaction to the presence and activity of an insect. The insect induces a differentiation of tissues with features and functions of an ectopic organ, providing nutrition and protection to the galling insect from natural enemies and environmental stresses. In this anatomical and cytological study, we characterized how the gall-inducing aphid Pemphigus betae reshapes the leaf morphology of the narrow-leaf cottonwood Populus angustifolia to form a leaf fold gall. Young galls displayed a bend on one side of the midvein toward the center of the leaf and back to create a fold on the abaxial side of the leaf. This fold was formed abaxially by periclinal and anticlinal divisions, effectively eliminating intercellular spaces from the spongy parenchyma. Galls at this stage exhibited both cell hypertrophy and tissue hyperplasia. Cells on the adaxial surface were more numerous and smaller than cells near the abaxial surface were, creating the large fold that surrounds the insect. Mesophyll cells exhibited some features typical of nutritive cells induced by other galling insects, including conspicuous nucleolus, reduced and fragmented vacuole, smaller and degraded chloroplasts, and dense cytoplasm compared to ungalled tissue. Even though aphids feed on the contents of phloem and do not directly consume the gall tissue, they induce changes in the plant vascular system, which lead to nutrient accumulation to support the growing aphid numbers in mature galls.

Changes in fruit quality parameters of ‘Jonathan Rasa’ and ‘Delicious Flanagan’ apples in response to elevated temperatures

Abstract Attached apples on trees of ‘Jonathan Rasa’ and ‘Delicious Flanagan’ (Malus x domestica Borkh.) were enclosed in polyethylene bags or left unbagged for 5 d in 2002 and 2004 to determine the effect of elevated temperatures just before harvest on fruit quality parameters measured immediately thereafter. Mean maximum daily air temperatures within the bags were 5 to 9°C warmer than those of the air, recorded in full sun. Mean maximum daily fruit surface and flesh temperatures of bagged apples were 5 to 12°C warmer than those of unbagged fruit. Maximum daily fruit surface and flesh temperatures of bagged apples were similar. Peel color (L*, chroma, hue) of both cultivars was altered by the bagging treatment, but not flesh firmness. Bagged fruit generally had a lower soluble solids concentration (SSC) and starch index rating than those of unbagged apples. Titratable acidity of bagged apples was generally lower than that of unbagged fruit. Respiration rate of bagged apples more than doubled with a 3 to 4°C increase in air temperature. Thus, several fruit quality parameters were adversely affected by elevated temperatures over a 5 day period.

Mobile Image Analysis for Microscopic Images of Seeds

Seeds sustain the beginning stage of a plant [1]. Seed kernel size and shape are crucial because they represent one of the major components of yield [2]. Therefore, it is important to develop an accurate, lowcost, and high-throughput morphometry method that allows for a detailed analysis of seed samples for the purpose of testing plant yield and vigor. Traditional methods of measuring individual seed morphometry or counting seeds in a cluster involve heavy manual work [3]. They have been proven to be labor-intensive, slow and inconsistent. Several tools that are based on image analysis have been developed to accelerate the measuring process, but it still requires a considerable length of time for sample preparation since the seeds need to be carefully placed either on a tray or a scanner in most cases. For accuracy, seeds should not be touching each other during the measurement. Ensuring so is particularly hard for small seeds such as Arabidopsis seeds.