Consumer behaviour towards vegetables: a study on domestic processing of broccoli and carrots by Dutch households

Diet quality, food intake and incident adult-onset asthma: a Lifelines Cohort Study

PURPOSE

Dietary factors have been suggested as drivers of the rising prevalence of adult-onset asthma, but evidence is inconclusive, possibly due to the complex interrelation with obesity. We aim to explore the relation of diet quality and food intake with incident adult-onset asthma in normal weight and overweight adults of the prospective population-based Lifelines Cohort Study.

METHODS

Incident adult-onset asthma was defined as self-reported asthma at ± 4-year follow-up, in adults free of airway disease at baseline. Diet quality scores and food group intake were assessed at baseline. Log-binomial regression analyses were used to estimate adjusted relative risks (RR) between dietary intake (per portion) and incident adult-onset asthma, in categories of BMI (cutoff: 25 kg/m²).

RESULTS

477 incident asthma cases (75% female, 62% overweight) and 34,698 controls (60% female, 53% overweight) were identified. Diet quality-assessed by the Lifelines Diet Score and Mediterranean Diet Score-was not associated with incident adult-onset asthma in the two BMI groups. Although the dietary intake of several food groups differed between cases and controls, after adjustment for confounders only few remained associated with adult-onset asthma, including red and processed meat (RR: 0.93 per 15 g intake; 95% CI 0.86-0.99) in the normal weight group and intake of cheese (RR 1.09 per 20 g intake; 95% CI 1.00-1.17) and vegetables (RR 1.10 per 50 g intake; 95% CI 1.00-1.21) in the overweight group.

CONCLUSION

The results of this study question the role of food as a 'simple' predictor of adult-onset asthma and call for an integrative approach, including a range of modifiable lifestyle factors and further asthma phenotyping.

What are the determinants of vegetable intake among adolescents from socioeconomically disadvantaged urban areas? A systematic review of qualitative studies

BACKGROUND

Evidence available on the determinants of vegetable intake in young populations is inconsistent. Vegetable intake is particularly low in adolescents from less-affluent backgrounds, yet no systematic review of qualitative studies investigating determinants for vegetable intake specifically has been conducted to date in this group. This systematic review aimed to identify determinants of vegetable intake in adolescents from socioeconomically disadvantaged urban areas located in very high-income countries reported in qualitative studies.

METHODS

Five electronic databases (PubMed, Web of Science, CINAHL, PsycINFO and ERIC) were searched until August 2022. The search strategy used combinations of synonyms for vegetable intake, adolescents, and qualitative methodologies. Main inclusion criteria were studies exploring views and experiences of motivators and barriers to vegetable intake in a sample of adolescents aged 12-18 years from socioeconomically disadvantaged urban areas in very high income countries. Study quality assessment was conducted using criteria established in a previous review.

RESULTS

Sixteen studies were included out of the 984 screened citations and 63 full texts. The synthesis of findings identified the following determinants of vegetable intake: sensory attributes of vegetables; psychosocial factors (nutrition knowledge, preferences/liking, self-efficacy, motivation); lifestyle factors (cost/price, time, convenience); fast food properties (taste, cost, satiety); home environment and parental influence; friends' influence; school food environment, nutrition education and teachers' support; and availability and accessibility of vegetables in the community and community nutrition practices. Studies attained between 18 and 49 out of 61 quality points, with eleven of 16 studies reaching ≥ 40 points. One main reason for lower scores was lack of data validation.

CONCLUSION

Multiple determinants of vegetable intake were identified complementing those investigated in quantitative studies. Future large scale quantitative studies should attempt to examine the relative importance of these determinants in order to guide the development of successful interventions in adolescents from socioeconomically disadvantaged backgrounds.

Cooking at home to retain nutritional quality and minimise nutrient losses: A focus on vegetables, potatoes and pulses

Cooking at home has experienced a decline in many countries since the mid-20th century. As rates of obesity have increased, there has been an emphasis on more frequent home cooking, including its incorporation into several food-based dietary guidelines around the world as a strategy to improve dietary quality. With the recent trend towards the adoption of diets richer in plant-based foods, many consumers cooking at home may now be cooking plant foods such as vegetables, potatoes and pulses more often. It is, therefore, timely to explore the impact that different home cooking methods have on the range of nutrients (e.g. vitamin C and folate) and bioactive phytochemicals (e.g. carotenoids and polyphenols) that such plant foods provide, and this paper will explore this and whether advice can be tailored to minimise such losses. The impact of cooking on nutritional quality can be both desirable and/or undesirable and can vary according to the cooking method and the nutrient or phytochemical of interest. Cooking methods that expose plant foods to high temperatures and/or water for long periods of time (e.g. boiling) may be the most detrimental to nutrient content, whereas other cooking methods such as steaming or microwaving may help to retain nutrients, particularly those that are water-soluble. Dishes that use cooking liquids may retain nutrients that would have been lost through leaching. It may be helpful to provide the public with more information about better methods to prepare and cook plant foods to minimise any nutrient losses. However, for some nutrients/phytochemicals the insufficient and inconsistent research findings make clear messages around the optimal cooking method difficult, and factors such as bioaccessibility rather than just quantity may also be important to consider.

How to Measure Organic Fruit Consumer Behavior: A Systematic Review

This review article seeks to systematically identify appropriate ways to measure the consumption behavior of organic fruits. The systematic review of the literature was performed according to the criteria of the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines, and the eligibility criteria were declared through the PICOS (population, interventions, comparators, outcomes, and study) tool based on 277 article records scientiometrically identified in both the Journal Citation Report databases from Web of Science. The literature review stages determined a reduced set of articles that presented valid and reliable measurement scales that covered determinant constructs in organic fruit consumer behavior (OFCB). The measurement scale with the best results reported within the screened articles covered the constructs related to health, fear, environment, effort, and economy, allowing it to serve as a reference instrument in further studies on food consumer behavior.

Influence of Cooking Method on the Nutritional Quality of Organic and Conventional Brazilian Vegetables: A Study on Sodium, Potassium, and Carotenoids

Vegetable consumption is associated with increased health benefits, and vegetables are consumed both in cooked form and raw form in salads. All cooking techniques cause changes in a vegetable’s the nutrient content. Consumers are increasingly health-conscious and have less time to prepare meals, and they do not know which cooking times and cooking methods are best suited to preserve the nutrients. This study aimed to determine the best method of cooking vegetables to maintain minerals (potassium and sodium) and carotenoids. The studied vegetables were broccoli (Brassica oleracea, var. Italica), carrots (Daucus carota), and zucchini (Cucurbita moschata). The cooking methods were: boiling, steaming, combined oven, microwave steaming, and microwave cooking. Samples of organic and conventionally grown vegetables were prepared in triplicate. Samples were analyzed to determine the availability of target minerals and carotenoids in the raw food and in each recommended cooking situation according to technical standards. Only the carrot showed a higher concentration in organic cultivation for carotenoids in raw vegetables, with both zucchini and broccoli having higher concentrations when grown by conventional cultivation. The zucchini from organic cultivation presented a reduction of potassium and sodium, almost consistently, in all cooking techniques. Regarding the conventionally cultivated zucchini, potassium remained stable in boiling. Broccoli from organic and conventional cultivation showed similar potassium levels for boiling and traditional steam cooking. Organic carrots showed easier sodium extraction compared with conventional cultivation. Heat treatment, in general, improves the accessibility of carotenoids.

Factors related to sensory properties and consumer acceptance of vegetables

Many consumers perceive the bitter taste or other sensory characteristic of vegetables as unpleasant, posing a challenge to dietary recommendations aiming to increase vegetable consumption. Food experience is multisensory, with complex interactions between the senses and individual differences in sensory perception. This review focuses on the factors affecting sensory properties of vegetables and sensory perception of vegetables among adults. Topical examples of sensory quality and evaluation of vegetable samples are presented. Cultivar and growing conditions are related to the internal sensory quality of vegetables. The effects of different processing methods, such as freezing and cooking, on the sensory properties of vegetables are also reviewed. Flavor modification of vegetables with seasonings may be used to improve palatability and incorporating vegetables to meals may increase the intake of vegetables. Recently, external factors (e.g. visual and odor stimuli) have been tested in multisensory research in the context of vegetable perception and choice. These options to achieve better sensory quality, more palatable meals and pleasant eating context may be used to promote vegetable intake among adults.

Consumers' Perceptions and Preferences for Bitterness in Vegetable Foods: The Case of Extra-Virgin Olive Oil and Brassicaceae-A Narrative Review

The presence of some healthy phytochemicals in food can be paired with high bitterness, and consumers have a widespread avoidance toward bitter-tasting food. This causes a gap between preferences and healthy needs of consumers. Therefore, this review collected insights from literature belonging to different discipline domains in order to have a broad view of the current state-of-the-art about biochemical aspects and consumers’ perceptions and preferences toward foods with an enhanced bitter taste. In detail, we focused on two core products of the Mediterranean diet: Extra-virgin olive oil (EVOO) and Brassicaceae, both characterized by specific phytochemicals having strong healthy properties and bitter-pungent taste. Results suggested that, although bitter taste is a general driver of dislike, some exceptions can be represented by: niches of consumers (e.g., innovators and organic buyers), foods consumed with specific purposes (e.g., coffee, chocolate, and alcoholic beverages). The level of bitterness perceived by the consumers can be modulated through exposure, information on benefits, and elements within the environment (e.g., music). Thus, these insights can be used to develop specific campaigns aimed at promoting bitter (healthy) food, considering also the key role that could be played by food pairings.

A multidisciplinary research agenda for the acceptance of Golden Rice

Purpose

The world is facing serious global food security challenges such as the need for sufficient food for a growing population and an exponential growth in nutrient deficiency disorders. Agricultural biotechnology, such as genetically modified (GM) crops, offers itself as a promising solution to address one or more of these issues. Golden Rice (GR) is an example of a GM crop which contains high amount of β-carotene, a compound which is an antioxidant and a precursor of vitamin A. In spite of GR’s promised potential benefits in combating vitamin A deficiency (VAD) disorders it is still not cultivated. This viewpoint paper aims to present the reader with a need for multidisciplinary research agenda, the outcomes of which can contribute towards the acceptance of GR.

Design/methodology/approach

This viewpoint paper is based on an extensive literature review to identify the “gaps” which contributed to low acceptance of GR. This paper presents a systematic discussion on the importance of GR in tackling VAD and discusses controversies around GR and a scientific approach to tackle them.

Findings

The literature review clearly indicates that there is a huge gap in information substantiating the potential of GR for consumers as well as for the farming community. Addressing these issues can substantially increase the acceptance and cultivation of GR. This viewpoint paper proposes food technologists’ and social scientists’ research agenda for GR and further indicates how the involvement of other research disciplines can improve the acceptance of GR.

Originality/value

The literature review indicates the potential of GR in tackling VAD disorders but clearly lacks information to substantiate these arguments. This paper presents authors’ opinions, urging scientists to take up a multidisciplinary research approach to emancipate GR from the clutches of GM food controversies.

Increasing vegetable intakes: rationale and systematic review of published interventions

Purpose

While the health benefits of a high fruit and vegetable consumption are well known and considerable work has attempted to improve intakes, increasing evidence also recognises a distinction between fruit and vegetables, both in their impacts on health and in consumption patterns. Increasing work suggests health benefits from a high consumption specifically of vegetables, yet intakes remain low, and barriers to increasing intakes are prevalent making intervention difficult. A systematic review was undertaken to identify from the published literature all studies reporting an intervention to increase intakes of vegetables as a distinct food group.

Methods

Databases—PubMed, PsychInfo and Medline—were searched over all years of records until April 2015 using pre-specified terms.

Results

Our searches identified 77 studies, detailing 140 interventions, of which 133 (81 %) interventions were conducted in children. Interventions aimed to use or change hedonic factors, such as taste, liking and familiarity (n = 72), use or change environmental factors (n = 39), use or change cognitive factors (n = 19), or a combination of strategies (n = 10). Increased vegetable acceptance, selection and/or consumption were reported to some degree in 116 (83 %) interventions, but the majority of effects seem small and inconsistent.

Conclusions

Greater percent success is currently found from environmental, educational and multi-component interventions, but publication bias is likely, and long-term effects and cost-effectiveness are rarely considered. A focus on long-term benefits and sustained behaviour change is required. Certain population groups are also noticeably absent from the current list of tried interventions.

Evaluation of different cooking conditions on broccoli (Brassica oleracea var. italica) to improve the nutritional value and consumer acceptance

The objective of this study was to gain insights into the effect of the cooking method on the liking as well as the retention of glucosinolates in broccoli. With this knowledge it can be concluded whether the health aspects of broccoli be improved by the cooking method without deteriorating sensory perception. For this, broccoli was cooked by methods commonly applied by consumers: boiling with a cold (water) start; boiling with a hot (water) start; and steaming. Firmness, greenness and amount of total glucosinolates in cooked broccoli were instrumentally determined. Sensory evaluation by untrained consumers (n = 99) for liking and sensory attributes intensity rating were performed on broccoli cooked by steaming and boiling-cold start at three time points, which resulted in 'high', 'medium', 'low' firm broccoli samples. At the end of cooking, steaming showed an increase in the amount of total glucosinolates (+17%). Boiling-hot start (-41%) and boiling-cold start (-50%) showed a decrease in amount of total glucosinolates. Sensory evaluation did not show statistically significant differences between steaming and boiling-cold start in liking at 'high' and 'medium' firmness; and in the attribute intensity ratings (except for juiciness at 'medium' firmness, and flavour at 'medium' and 'low' firmness). This study demonstrates that medium firm broccoli showed optimum liking and that steaming compared to boiled-cold start showed higher amount of glucosinolates. It is concluded that the health aspects of broccoli can be improved without reducing the sensory aspects by optimising the cooking method.