Factors related to sensory properties and consumer acceptance of vegetables

Preparation Methods and Perceived Risk of Foodborne Illness Among Consumers of Prepackaged Frozen Vegetables - United States, September 2022

Listeria monocytogenes causes listeriosis, a serious infection, with a high mortality rate for persons at higher risk for listeriosis. The first Listeria outbreak linked to frozen vegetables occurred in 2016 and resulted in three deaths. Many frozen vegetables are intended to be consumed after cooking. However, data on consumer behavior are sparse. We characterized consumers' perceptions of contamination of prepackaged frozen vegetables, and preparation methods of prepackaged frozen vegetables to help inform prevention strategies. During September 1-24, 2022, Porter Novelli Public Services conducted the FallStyles survey using the Ipsos KnowledgePanel. Data were weighted to be representative of the U.S. population. Point estimates and 95% CIs were calculated and differences between respondents were determined using Wald chi square tests. Among 3,008 respondents reporting a preparation and consumption method for frozen vegetables, 8.7% (95% CI = 7.4%-10.0%) reported ever consuming the product raw. Respondents who reported having children <18 years old were more likely to report ever consuming frozen vegetables raw compared with respondents who did not (12.5% vs. 7.4%, p<0.01). The most reported raw preparation method was adding them directly to a blender for smoothie or juice (5.6%; 95% CI = 4.6%-6.7%). Among respondents who reported eating frozen vegetables, 59.6% (95% CI = 57.6%-61.6%) reported following package instructions. A third (34.1% [95% CI = 32.2%-35.9%]) of respondents agreed that frozen vegetables can be contaminated with germs (like Salmonella, E. coli, and Listeria), with a greater proportion of people with cancer disagreeing compared to those without cancer (32.5% vs 23.4%, p=0.041). These findings show that some consumers may not be cooking frozen vegetables before eating them. Second, consumers might not be reading instructions on packaging. Both findings highlight the critical importance of preventive controls in the production of frozen vegetables prior to reaching the consumer.

Synergist effect of thermosonication and NaCl on inactivation of Staphylococcus aureus and Shigella flexneri in lettuce: The effect of acoustic field and reaction kinetics

The study aimed to investigate the effect of thermosonication (TS; 37 KHz, 300 W; 30, 40, 50, and 60 °C for 10 min) and NaCl (12 % w/v) on the inactivation of Staphylococcus aureus and Shigella flexneri in lettuce, as well as to examine the kinetics of inactivation and the thermodynamic behaviors of the process. Computational Fluid Dynamics (CFD) simulations were employed to analyze the acoustic pressure field, velocity contours, and streamlines. The results showed that NaCl addition had the least impact on inactivation compared to TS and combined NaCl + TS. Increasing the temperature led to higher inactivation of both bacteria, with a more significant effect at 60 °C. Thermosonication treatment had a more consistent effect on inactivation compared to the addition of NaCl. When exposed to thermosonication, the population of S. aureus and S. flexneri could be reduced by 5.1 to 6.9 log CFU/g and 5.5 to 7.4 log CFU/g, respectively, at temperature levels of 30 and 60 °C. Additionally, no significant relationship between entropy reduction and type of microorganisms was observed. The samples that were treated only with NaCl had higher energy absorption than the other samples.

Impact of Visual Cues on Consumers' Freshness Perception of Prepared Vegetables

Freshness is an important quality attribute for vegetables. Identifying the sensory drivers for freshness is important to promote vegetable consumption. Due to the lack of research on freshness of prepared vegetables, this study focused on the role of visual cues of common vegetables (carrot, beetroot, bell pepper) on perception of freshness. Twenty-seven vegetables were prepared by varying five factors and photographed in a plate: (1) shape (stick, large cube, small cube), (2) vegetable presence for each of the three vegetables (yes, no), (3) number of vegetables conjointly present in the plate (1, 2, 3), (4) color (green bell pepper, yellow bell pepper), (5) combined vegetables prepared with same or different shapes. Freshness was rated online by 156 consumers. Visual cues leading to the main increase in freshness were the stick shape vs. large and small cubes, the absence of beetroot, and the presence of green bell pepper vs. yellow bell pepper. Overall, it seems that visual cues associated with minimally processed vegetables, such as stick shapes, which allow to recognize the vegetables in comparison to cube shapes, promote freshness. These results are particularly valuable for culinary and catering professionals and food industries involved in the preparation and/or manufacturing of prepared vegetables.

How do pretreatment and frozen storage impact the volatile profiles of Brussels sprouts and leek?

The volatile profiles of Brussels sprouts and leek, as affected by pretreatment combined with frozen storage were analyzed in the present work. The data revealed that, notwithstanding the effect upon pretreatment seemed to be major compared to the effect upon frozen storage, the latter was existent. Pretreatment yielded volatile compounds that could be associated with (bio)chemical reaction pathways in both vegetables. For frozen storage at -20 °C, the effect for leek appeared to be the largest for the blanched and raw samples, possibly due to a substantial amount of substrates present when frozen storage was initiated in this sample compared to the other samples. Those substrates were apparently more prone to be affected upon frozen storage. For Brussels sprouts, this observation was less outspoken. Remarkably, the abundance of markers in pretreated Brussels sprouts seemed to show a decreasing linear trend towards the end of the frozen storage period at -20 °C. As industrial relevant conditions were considered and compared, the insights gained in this study might be relevant to implement on industrial level.

A Lexicon of Descriptive Sensory Terms for Peas (Pisum sativum L.): A Systematic Review

BACKGROUND

The popularity of peas (Pisum sativum L.) and pea-derived products is constantly growing globally and is estimated to continue to do so at an average annual rate of 12%. This is partially stimulated by the increase in the consumption of meat analogues and the popularisation of animal-protein-free diets. Peas are considered a great source of protein and dietary fibre and are not depicted as allergenic, making them a good replacement ingredient for other legumes such as soy. Peas are also considered good for the environment, mainly due to their nitrogen fixation capabilities. Despite the above benefits, sensory quality is still a limiting factor in increasing consumer acceptance of peas and pea-derived products.

RESULTS

This review has been conducted in accordance with the Joanna Brings Institute's guidance for systematic literature reviews. The search has been conducted on the descriptive sensory terms for Pisum sativum L., where the objectives of the study were to select, present, and analyse the identified descriptive sensory terms for peas found throughout the academic literature. The reviewers have screened 827 articles, of which 12 were eligible for data extraction. Out of the 12 articles, 205 descriptive sensory terms were identified. Those were divided into five categories: smell/odour (27%), flavour (51%), taste (10%), texture (8%), and visual (4%). These included results from sensory analyses by trained/untrained panels and instrumental analyses of texture and of volatile compounds.

CONCLUSION

The identified descriptive sensory terms for Pisum sativum L. could be used for future descriptive sensory evaluation of peas and other legumes, making the process less time consuming. The full list could be used for the initial sensory panel training and then adapted based on the frequency of the depicted terms that meet the criteria for the developed lexicon.

Predictors of Eating Less Meat and More Plant-Based Food in the Polish Sample

The study aimed to identify predictors of the intention to eat less meat and more plant-based foods, including attitudes towards eating meat, habitual meat eating, subjective norms, and self-identity. A cross-sectional study using CAWI (Computer-Assisted Web Interview) was conducted in a group of 1003 Polish adults in 2023. To measure the predictor variables, the following tools were used: Beliefs and Eating Habits Questionnaire (KomPAN), Meat Attachment Questionnaire (MAQ), and scales to measure subjective norms and self-identity. Logistic regression analysis was used to verify associations between independent variables, and the intentions to eat more plant-based food and less meat next year were treated as dependent variables. More respondents were willing to increase their consumption of plant-based foods rather than reduce their meat consumption. The intention to consume less meat and more plant foods was more prevalent among women, older people (only intention to reduce meat consumption), and better-educated people (only intention to increase plant food consumption). Habitual frequency of eating plant foods, negative feelings about meat, and environmentally oriented identities had a stimulating effect on the intention to eat more plant foods and less meat, while experiencing pleasure in eating meat had a limiting effect on the intention to eat more plant foods and less meat. In addition, the habitual frequency of meat consumption and subjective norms reduced the likelihood of eating less meat, while no predictive effect was observed for the intention to eat more plant foods. In conclusion, educational and promotional activities to raise awareness of the link between food consumption and the environment can have a strong impact on eating less meat and more plant-based food, even among those strongly accustomed to meat consumption.

6-BA Delays the Senescence of Postharvest Cabbage Leaves by Inhibiting Respiratory Metabolism

6-BA, a small molecule compound of cytokinins, has been proven to delay leaf senescence in different species, including Chinese flowering cabbage; however, its specific mechanism remains relatively unknown. In this study, the application of external 6-BA delayed leaf senescence in Chinese flowering cabbage, showing that 6-BA effectively prevented the decrease in the maximum quantum yield (Fv/Fm) and overall chlorophyll content and suppressed the expression of the senescence-associated gene BrSAG12 over a 7-day period of storage. Moreover, treatment with 6-BA decreased the respiratory rate, NAD(H) content, the activities of hexose phosphate isomerase (PHI), succinate dehydrogenase (SDH), cytochrome c oxidase (CCO), and ascorbic acid oxidase (AAO) using enzyme-linked immunosorbent assay, and the transcriptional abundance of related genes by real-time quantitative polymerase chain reaction. Furthermore, 6-BA also increased the activity and expression levels of glucose-6-phosphate dehydrogenase (G6PDH) and 6-phosphate gluconate dehydrogenase (6-PGDH). The group treated with 6-BA retained elevated levels of NADP (H), ATP, total ATPase, and nicotinamide adenine dinucleotide kinase (NADK) activity, as well as the expression of respiratory enzymes. Molecular docking indicated that 6-BA hinders the glycolysis pathway (EMP), tricarboxylic acid cycle (TCA), and cytochrome pathway (CCP), and sustains elevated levels of the pentose phosphate pathway (PPP) through interactions with the PHI, SDH, 6-PGDH, G6PDH, CCO, and AAO proteins, consequently delaying postharvest leaf senescence in Chinese flowering cabbage.

Simply red? The effects of distinct colours and sustainable production methods on the consumers' preferences for healthier sweet peppers

The purpose of this paper is to thoroughly assess the value of colours in consumers' preferences for sweet peppers, and the association with more sustainable methods of production in the consumers' minds. Furthermore, this study provides novel insights into the influence of colours on the willingness to pay (WTP) for vegetables. It explores the interplay between colours, food attributes, and socio-demographic characteristics among consumers, marking the first attempt to examine this relationship comprehensively. A discrete choice experiment, based on consumers' preferences for sweet pepper attributes (price, colour, and production method), was implemented and a Seemingly Unrelated Regression model was then applied to evaluate the willingness to pay for different colours. The study has revealed that different colours provide consumers with different utilities and WTP in the choices of potential healthier foods. In addition, gender, age, education and number of family components play a role in affecting consumers' WTP of food linked to colour. Finally, it was found that consumers' knowledge for certain pepper colours with different antioxidant contents is interrelated. This study introduces several novelties, in particular a positive correlation between interest in antioxidants and colours was found, suggesting that interest in healthy food properties might move consumers towards a specific sensory choice.

A sensory lexicon to characterize the quality of fresh and preserved peppers

Pepper fruits (Capsicum annuum) are economically important commodities worldwide due to their unique sensory profiles and rich antioxidant properties. With ongoing research efforts in optimizing the production and processing of peppers, there is a need for a standardized tool to evaluate the quality of peppers and pepper products. The objective of this work was to develop a sensory lexicon to characterize fresh and preserved peppers. A panel of 10 volunteers was recruited and trained in quantitative descriptive sensory analysis for a total of 37 h. Commercially available fresh, pickled, and roasted peppers were used to establish definitions, methods of evaluation, and reference materials for each unique attribute; and attribute intensities were scored on a scale ranging from 0 to 15. Commercially available fresh and preserved pepper samples (n = 22) were evaluated by the panel in duplicate to validate the lexicon. Principal component analysis was used to visualize differences among the products, and attribute redundancies were evaluated through analysis of correlations. This lexicon with 46 clearly defined terms that describe fresh, pickled, and roasted pepper products is comprised of 14 aroma, 19 flavor, 9 texture, and 4 chemesthetic attributes. Smoky, burnt, and cooked tomato flavors were typical of roasted red bell peppers, while the floral attribute was characteristic of fresh red bell peppers, and vinegar, pungency, and spicy notes characterized pickled peppers. The lexicon enabled the characterization and differentiation of a wide range of pepper products and lays the framework for quality evaluation and product improvement. PRACTICAL APPLICATION: Breeders and processors are seeking technologies that ensure desirable quality of fresh and processed peppers for an extended shelf life. This sensory lexicon comprised of 14 aroma, 19 flavor, 9 texture, and 4 chemesthetic attributes serves as a basis for evaluating various strategies toward quality improvement, such as novel processing of pepper products.

Preliminary Comparisons of Tender Shoots and Young Leaves of 12 Mulberry Varieties as Vegetables and Constituents Relevant for Their Potential Use as Functional Food for Blood Sugar Control

Vegetables are essential for maintaining health and preventing diseases due to their nutrients and functional components. However, vegetables specifically designed for blood sugar control are limited. The mulberry tree (Morus) offers potential as a source of functional vegetables with blood-sugar-lowering properties, mainly attributed to 1-Deoxynojirimycin (DNJ). This study compared the nutritional composition and DNJ content in various edible parts of twelve mulberry tree varieties. Sensory evaluations were also conducted to assess sensory attributes. Interestingly, DNJ was found to show a positive correlation with sensory evaluations. Furthermore, the sugar content, particularly sucrose, was significantly higher in tender shoots than leaves, indicating tender shoots as a preferable choice for development as a functional food for blood sugar control. Finally, VM 19 and VM 22 are considered as good candidates for the mulberry vegetable using varieties after sensory evaluation and combining with the DNJ content. These findings provide valuable insights for future research into vegetable selections for blood sugar management and support the potential commercialization of mulberry leaf vegetables as functional food options.

Responsiveness to warning sensations and anxiety-related psychological traits modulate individual differences in preference for vegetable foods with varied sensory properties

The innate aversion to warning sensations is an important barrier to the acceptance of vegetable food often characterized by bitter and sour tastes, and astringency. Large individual variations exist in preference for this food category. The present study aimed at exploring differences in demographics, anthropometrics, taste responsiveness, personality traits and attitudes in consumers differing in their preference for vegetable food with varied levels of warning sensations. A panel of Italian consumers (n = 718; 53.6% women, age 18-74 years) self-reported familiarity with, preference for and choice of vegetables with high and low levels of warning sensations. Two clusters were identified: High Warning-Vegetable Consumers (HWVC, n = 464) and Low-Warning Vegetable Consumers (LWVC, n = 254). HWVC showed higher familiarity with and preference for vegetables as a whole and higher choice of vegetables characterized by warning sensations than LWVC. HWVC were more represented by older and normal weight individuals as compared to LWVC. Differences among clusters in liking for and perception of a phenol-enriched plant-based food model specifically developed to induce different levels of bitterness, sourness and astringency were found. HWVC rated bitterness, sourness, and astringency lower and liking higher than LWVC. Scores in anxiety-related psychological traits were lower while attitudes to healthy and high-quality food choice were higher in HWVC than in LWVC. The results of the present study depicted a coherent interplay among several person-related dimensions in modulating preference for vegetable foods. Higher responsiveness to warning sensations, higher level of anxiety-related traits, lower importance assigned to food healthy/quality aspects and younger age all acted as barriers to exposure and acceptance of vegetable food and call for a multidimensional approach to promote the consumption of this food category.

Using machine learning for image-based analysis of sweetpotato root sensory attributes

The sweetpotato breeding process involves assessing different phenotypic traits, such as the sensory attributes, to decide which varieties to progress to the next stage during the breeding cycle. Sensory attributes like appearance, taste, colour and mealiness are important for consumer acceptability and adoption of new varieties. Therefore, measuring these sensory attributes is critical to inform the selection of varieties during breeding. Current methods using a trained human panel enable screening of different sweetpotato sensory attributes. Despite this, such methods are costly and time-consuming, leading to low throughput, which remains the biggest challenge for breeders. In this paper, we describe an approach to apply machine learning techniques with image-based analysis to predict flesh-colour and mealiness sweetpotato sensory attributes. The developed models can be used as high-throughput methods to augment existing approaches for the evaluation of flesh-colour and mealiness for different sweetpotato varieties. The work involved capturing images of boiled sweetpotato cross-sections using the DigiEye imaging system, data pre-processing for background elimination and feature extraction to develop machine learning models to predict the flesh-colour and mealiness sensory attributes of different sweetpotato varieties. For flesh-colour the trained Linear Regression and Random Forest Regression models attained R 2 values of 0.92 and 0.87, respectively, against the ground truth values given by a human sensory panel. In contrast, the Random Forest Regressor and Gradient Boosting model attained R 2 values of 0.85 and 0.80, respectively, for the prediction of mealiness. The performance of the models matched the desirable R 2 threshold of 0.80 for acceptable comparability to the human sensory panel showing that this approach can be used for the prediction of these attributes with high accuracy. The machine learning models were deployed and tested by the sweetpotato breeding team at the International Potato Center in Uganda. This solution can automate and increase throughput for analysing flesh-colour and mealiness sweetpotato sensory attributes. Using machine learning tools for analysis can inform and quicken the selection of promising varieties that can be progressed for participatory evaluation during breeding cycles and potentially lead to increased chances of adoption of the varieties by consumers.

A longitudinal analysis of Australian women's fruit and vegetable consumption and depressive symptoms

BACKGROUND

In Australia, women report higher rates of depressive symptoms than men. Research suggests that dietary patterns rich in fresh fruit and vegetables could protect against depressive symptoms. The Australian Dietary Guidelines suggest that consuming two servings of fruit and five serves of vegetables per day is optimal for overall health. However, this consumption level is often difficult for those experiencing depressive symptoms to achieve.

AIMS

This study aims to compare diet quality and depressive symptoms in Australian women over time using (I) two serves of fruit and five serves of vegetables per day (FV7), and (ii) two serves of fruit and three serves of vegetables per day (FV5).

MATERIALS AND METHODS

A secondary analysis was conducted using data from the Australian Longitudinal Study on Women's Health over 12 years at three time points 2006 (n = 9145, Mean age = 30.6, SD = 1.5), 2015 (n = 7186, Mean age = 39.7, SD = 1.5), and 2018 (n = 7121, Mean age = 42.4, SD = 1.5).

RESULTS

A linear mixed effects model found, after adjusting for covarying factors, a small significant inverse association between both FV7 (b = -.54, 95% CI = -.78, -.29) and FV5 (b = -.38, 95% CI = -.50, -.26) in depressive symptoms.

DISCUSSION

These findings suggest an association between fruit and vegetable consumption and decreased depressive symptoms. The small effect sizes indicate caution should be taken in interpreting these results. The findings also suggest that current Australian Dietary Guideline recommendations need not be prescriptive to two fruit and five vegetables for impact on depressive symptoms.

CONCLUSIONS

Future research could evaluate reduced vegetable consumption (three serves per day) in identifying the protective threshold for depressive symptoms.

A Comparative Analysis of Plant-Based Milk Alternatives Part 1: Composition, Sensory, and Nutritional Value

Consumers are becoming increasingly interested in reducing the consumption of animal-based foods for health, sustainability, and ethical reasons. The food industry is developing products from plant-based ingredients that mimic animal-based foods’ nutritional and sensory characteristics. In this study, the focus is on plant-based milk alternatives (PBMAs). A potential problem with plant-based diets is the deficiency of important micronutrients, such as vitamin B12, B2, and calcium. Therefore, an analysis of micronutrients in PBMAs was conducted to assess their nutritional value. The second main focus was on the sensory description of the PBMAs, done by a trained panel, and instrumental assessment to characterize the sensory attributes. Almond drinks met the daily micronutrient requirements the least, while soy drinks came closest to cow’s milk in macro- and micronutrients. The experimentally determined electronic tongue and volatile compound results confirmed the sensory panel’s evaluations and could therefore be used as a method for easy and effective assessments of PBMAs. The PBMAs evaluated in this study could not completely replace cow’s milk’s nutritional and sensory properties. They are products in their own product group and must be evaluated accordingly. Given the variety of products, consumers should experiment and make their decisions regarding the substitution of cow’s milk.