Isabella Endrizzi

Investigation of Volatile Compounds in Two Raspberry Cultivars by Two Headspace Techniques: Solid-Phase Microextraction/Gas Chromatography−Mass Spectrometry (SPME/GC−MS) and Proton-Transfer Reaction−Mass Spectrometry (PTR−MS)

The volatile compounds emitted by two raspberry varieties ( Rubus idaeus , cv. Polka and Tulameen) were analyzed, in both the case of fresh fruits and juices, by two headspace methods that are rapid, solvent-free, and with reduced or no sample pretreatment: solid-phase microextraction/gas chromatography-mass spectrometry (SPME/GC-MS) and proton-transfer reaction-mass spectrometry (PTR-MS). Multivariate analysis of the SPME/GC-MS results allows for an unambiguous sample discrimination for both mashed fruits and juices. PTR-MS instrumental fingerprint provides, in a faster way, similar qualitative information on the overall flavor profile. The two cultivars show both qualitative and quantitative differences. SPME/GC-MS analysis shows that alcohols and aldehydes are more abundant in the headspace of Tulameen as, e.g., hexanal and hexanol that induce herbaceous odor notes. This observation has been confirmed by sensory analysis. PTR-MS was also used to monitor rapid processes that modify the original aromatic profile, such as lipo-oxigenase activity induced by tissue damages occurring during industrial transformation, accidental mechanical damages, or as a consequence of chewing.

Food neophobia and its relation with olfaction.

Food neophobia, that is the reluctance to try novel foods, is an attitude that dramatically affects human feeding behavior in many different aspects among which food preferences and food choices appear to be the most thoroughly considered. This attitude has an important evolutionary meaning since it protects the individual from ingesting potentially dangerous substances. On the other hand, it fosters an avoidance behavior that can extend even toward useful food elements. A strong link exists between food neophobia and both the variety in one person’s diet and previous exposures to different foods. In this review, the more recent findings about food neophobia will be concisely described. Given the suggested connection between the exposure to different foods and food neophobia, this review will focus on the relation between this attitude and human chemosensory abilities. Olfaction, in particular, is a sensory modality that has a central role in flavor perception and in food preference acquisition. Therefore, the latest evidences about its relation with food neophobia will be discussed along with the applied and cognitive implications.

Effects of Pasteurization on Volatile Compounds and Sensory Properties of Coconut (Cocos nucifera L.) Water: Thermal vs. High-Pressure Carbon Dioxide Pasteurization

Coconut water is a tropical beverage with a distinctive odor and flavor that has until now not been adequately characterized. In the present paper, the volatile compound composition of coconut water was investigated using head space solid-phase microextraction-gas chromatography-mass spectrometry (HS-SPME-GC-MS). Analyses were made of fresh untreated (FU) samples and samples pasteurized using two different technologies: conventional thermal treatment (thermal pasteurization (TP)) and high-pressure carbon dioxide (HPCD) pasteurization, which has recently attracted great interest as an innovative nonthermal preservation treatment. Seventy-three volatile compounds were identified; 27 of them reported for the first time in coconut water. The results showed that HPCD treatment depletes short- and medium-chain alcohols, while TP treatment triggers an increase in aldehydes, ketones, and 2-acetyl-1-pyrroline, an aroma compound active at low odor thresholds and characterized by “popcorn” and “toasted” odor descriptors. Sensory discrimination analysis (triangle test) showed there to be no significant differences between HPCD and FU samples, while TP and FU samples were perceived significantly differently. Descriptive sensory analyses evidenced more intense “cooked,” “toasted bread,” and “hazelnut” characteristics in TP-treated coconut water, consistent with HS-SPME-GC-MS data. In conclusion, instrumentally measurable changes in volatile compounds were more moderate with HPCD than with TP treatment and were not sensorially perceivable compared with the FU product.

Sweet taste in apple: the role of sorbitol, individual sugars, organic acids and volatile compounds

Sweetness is one of the main drivers of consumer preference, and thus is given high priority in apple breeding programmes. Due to the complexity of sweetness evaluation, soluble solid content (SSC) is commonly used as an estimation of this trait. Nevertheless, it has been demonstrated that SSC and sweet taste are poorly correlated. Though individual sugar content may vary greatly between and within apple cultivars, no previous study has tried to investigate the relationship between the amount of individual sugars, or ratios of these, and apple sweetness. In this work, we quantified the major sugars (sucrose, glucose, fructose, xylose) and sorbitol and explored their influence on perceived sweetness in apple; we also related this to malic acid content, SSC and volatile compounds. Our data confirmed that the correlation between sweetness and SSC is weak. We found that sorbitol content correlates (similarly to SSC) with perceived sweetness better than any other single sugar or total sugar content. The single sugars show no differentiable importance in determining apple sweetness. Our predictive model based on partial least squares regression shows that after sorbitol and SSC, the most important contribution to apple sweetness is provided by several volatile compounds, mainly esters and farnesene.

A multi-product approach for detecting subjects’ and objects’ covariates in consumer preferences

– A different framework based on a parametric version of the process generating the hedonic scores is adopted. More precisely, a probability distribution for ordinal responses is proposed as a mixture of two components, denoted as feeling (as expressed preference) and uncertainty component (as inherent indecision). The purpose of this paper is to analyse the effect of covariates on the consumers’ behaviour pattern according to a statistical model. , – Sample data come from a multidisciplinary research aimed to improve the quality and marketability of soft fruits. Then, a stochastic model with subjects’ and objects’ covariates is built and the interpretation of significant results is discussed. , – The joint effects of personal characteristics and chemical contents of juice on the hedonic scores given by consumers are examined and graphically depicted by means of a significant model. , – The paper suggests a multi-product approach to expressed hedonic scores by means of a generalization of CUB models.

The effect of two orchard light management practices on the sensory quality of apple: fruit thinning by shading or photo-selective nets

Summary The effects of innovative techniques for orchard light management on the sensory properties and quality of apple (Malus _ domestica Borkh.) fruit were measured using sensory and instrumental techniques. In the first experiment, ‘Rosy Glow’ fruit, thinned chemically or by shading, were compared. In the second experiment, ‘Fuji’ fruit were grown under five different coloured photo-selective hail nets and compared. For ‘Rosy Glow’ fruit, the efficacy of both thinning methods was comparable in terms of crop load, and no sensory differences were perceived between treatments by a trained sensory panel, based on quantitative descriptive profiling, except for the “green flesh” attribute. Nevertheless, ‘Rosy Glow’ fruit from the shade-based thinning had a higher mean fresh weight (FW; 215 g vs. 198 g) and higher titratable acidity (5.3 vs. 4.5 malic acid eq. 100 g-1 juice). Some significant differences were reported by the trained sensory panel for four out of the ten attributes rated among the ‘Fuji’ apples produced under the neutral black net (control), and the red, white, yellow, and blue photo-selective hail nets. Differences were greatest between fruit from the red and yellow hail nets. Apples from the red hail net had higher scores for yellow colour perception (average intensity 42.3 vs. 28.5, based on a linear scale anchored at 0 as the minimum and 100 as the maximum), sweet taste (score 54.9 vs. 42.4), and hardness (i.e., sensory definition for firmness; score 52.0 vs. 43.0), and a lower score for green colour (4.6 vs. 10.0). In terms of objective instrumental measurements, fruit from the red net treatment had a higher mean FW (217 g), with larger cells and larger intercellular spaces measured in terms of the number of cells mm-3 and the percentage of intercellular spaces, and a higher mean dry matter (DM) content [14.7% (w/w)], when compared to fruit from the other photo-selective net treatments. The spectrum of transmitted light influenced fruit growth by affecting cell proliferation and ripening, which changed the sensory perceptions of fruit appearance, taste, and texture.This study demonstrated that it is possible to use sensory panel analysis to measure the impact of new pre-harvest treatments on the quality of harvested apple fruit.

Application of a Sensory-Instrumental Tool to Study Apple Texture Characteristics Shaped by Altitude and Time of Harvest

BACKGROUND Texture is important in the preferences of apple consumers. Of the pre-harvest factors affecting fruit quality and especially texture, altitude and subsequent climatic conditions are crucial, determining differences in the physiological mechanisms of fruit growth, ripening stage and chemical composition, as demonstrated by several studies. This work applies a detailed sensory-instrumental protocol developed in a previous paper to investigate the impact of altitude, time of harvest and their cross-effect on sensory characteristics of apple, with a focus on texture. RESULTS Sensory differences were found in relation to altitude, although the profile results were mainly affected by the time of harvest. Fruit from lower altitude was described as juicier, crunchier and sweeter than samples from higher altitude, which were floury, sourer and more astringent. Texture performance, soluble solids content and titratable acidity corroborated this sensory description. Moreover, anatomical data showed that fruit from lower altitude had a larger volume, a higher number of cells and a higher percentage of intercellular spaces. CONCLUSION We demonstrated that differences between fruit from various altitudes can be perceived through human senses, and that the proposed sensory-instrumental tool can be used to describe such differences. This study brings more understanding about the impact of altitude and time of harvest on apple sensory properties. This work could support apple producers, from semi-mountainous regions (Alps, Tyrol, etc.), in advertising and valorising their products with their specific characteristics in a more efficient manner.