Susann Zahn

Integrating sensory evaluation in adaptive conjoint analysis to elaborate the conflicting influence of intrinsic and extrinsic attributes on food choice.

Sensory properties and packaging information are factors which considerably contribute to food choice. We present a new methodology in which sensory preference testing was integrated in adaptive conjoint analysis. By simultaneous variation of intrinsic and extrinsic attributes on identical levels, this procedure allows assessing the importance of attribute/level combinations on product selection. In a set-up with nine pair-wise comparisons and four subsequent calibration assessments, 101 young consumers evaluated vanilla yoghurt which was varied in fat content (four levels), sugar content (two levels) and flavour intensity (two levels); the same attribute/level combinations were also presented as extrinsic information. The results indicate that the evaluation of a particular attribute may largely diverge in intrinsic and in extrinsic processing. We noticed from our utility values that, for example, the acceptance of yoghurt increases with an increasing level of the actual fat content, whereas acceptance diminishes when a high fat content is labelled on the product. This article further implicates that neglecting these diverging relationships may lead to an over- or underestimation of the importance of an attribute for food choice.

A Combination of Fat Replacers Enables the Production of Fat-reduced Shortdough Biscuits with High-sensory quality

Because of the increasing number of overweight consumers, a decrease of the daily energy intake without changing the palatability of foods is of tremendous importance. This study was performed to replace 30% or 40% fat in the formulation with a single fat replacer (corn fibre, maltodextrin or lupine extract) or a binary combination thereof and to investigate its impact on product characteristics (moisture, volume, colour and texture) and sensory properties of the biscuits. The replacement of 30% baking fat resulted in increased moisture content after baking, volume increase was significantly lower than for reference biscuits, biscuit colour was affected and the firmness increased drastically. Forty percent fat replacement increased these differences. Quantitative descriptive analysis revealed deviations, which were in line with analytical results and which were highest when lupine extract was used as fat replacer. The deviation to a reference biscuit was subsequently reduced by using appropriate combinations of the investigated fat replacers. One of those combinations, with corn fibre and lupine extract in a ratio of 1:1 replacing 30% baking fat, was given priority in a consumer test with a total of 192 respondents.

Ultrasonic excitation affects friction interactions between food materials and cutting tools.

In the food industry, ultrasonic cutting is used to improve separation by a reduction of the cutting force. This reduction can be attributed to the modification of tool-workpiece interactions at the cutting edge and along the tool flanks because of the superposition of the cutting movement with ultrasonic vibration of the cutting tool. In this study, model experiments were used to analyze friction between the flanks of a cutting tool and the material to be cut. Friction force at a commercial cutting sonotrode was quantified using combined cutting-friction experiments, and sliding friction tests were carried out by adapting a standard draw-off assembly and using an ultrasonic welding sonotrode as sliding surface. The impact of material parameters, ultrasonic amplitude, and the texture of the contacting food surface on friction force was investigated. The results show that ultrasonic vibration significantly reduces the sliding friction force. While the amplitude showed no influence within the tested range, the texture of the contact surface of the food affects the intensity of ultrasonic transportation effects. These effects are a result of mechanical interactions and of changes in material properties of the contact layer, which are induced by the deformation of contact points, friction heating and absorption heating because of the dissipation of mechanical vibration energy.

Processing- and product-related causes for food waste and implications for the food supply chain

Reducing food waste is one of the prominent goals in the current research, which has also been set by the United Nations to achieve a more sustainable world by 2030. Given that previous studies mainly examined causes for food waste generation related to consumers, e.g., expectations regarding quality or uncertainties about edibility, this review aims at providing an overview on losses in the food industry, as well as on natural mechanisms by which impeccable food items are converted into an undesired state. For this, scientific literature was reviewed based on a keyword search, and information not covered was gathered by conducting expert interviews with representatives from 13 German food processing companies. From the available literature, three main areas of food waste generation were identified and discussed: product deterioration and spoilage during logistical operations, by-products from food processing, and consumer perception of quality and safety. In addition, expert interviews revealed causes for food waste in the processing sector, which were categorised as follows: losses resulting from processing operations and quality assurance, and products not fulfilling quality demands from trade. The interviewees explained a number of strategies to minimise food losses, starting with alternative tradeways for second choice items, and ending with emergency power supplies to compensate for power blackouts. It became clear that the concepts are not universally applicable for each company, but the overview provided in the present study may support researchers in finding appropriate solutions for individual cases.

Implicit food associations as obstacles to healthy nutrition: the need for further research:

Healthy nutrition is the driving force behind measures to address the obesity and diabetes epidemic. Therefore, the relevance of healthy nutrition to public health is steadily increasing. Although many consumers have positive attitudes towards healthy nutrition, their eating habits do not always match these attitudes. This paper suggests that individuals can overcome the discrepancy between attitude/intention and behaviour if they consider implicit associations with healthy or unhealthy nutrition. Our paper aims to develop a research strategy to analyse the impact of the interplay between explicit and implicit food associations on food consumption. The suggested process comprises the following steps: consumer segmentation, isolated analysis of different implicit drivers, holistic examination of interaction effects of different drivers and development of implications for policy makers and managers. Br J Diabetes Vasc Dis 2011;11:182-186

Tailoring compensation effects of health-unrelated food properties

With the steady rise of the adiposity epidemic, there are increasing calls to stimulate healthier food choices. This is difficult, however, because consumers hold the nearly universal belief that healthy foods are less tasty. To increase their attractiveness, optimizing certain health-unrelated food attributes may help compensate for the loss in taste that is caused by the reduction of fat or sugar. The overall objective of this paper is to examine the boundary conditions under which such compensation effects emerge. Using the example of cookies, we examine how compensation effects depend on (i) the consumer segment, (ii) the configuration of the food product, and (iii) the type of evaluation process. This paper empirically tests compensation effects for optimized flavor intensity. We apply a combination of adaptive conjoint analysis and sensory preference tests. Market simulations and sensitivity analyses demonstrate that the intricate interplay among the three contingency variables is far more important than the question of whether compensation effects emerge or not. The analyses uncover four distinct segments and they show that compensation effects depend on which type of health-related attribute is reduced and whether the health-unrelated attribute is improved intrinsically or extrinsically.

Visually suboptimal bananas: How ripeness affects consumer expectation and perception

One reason for the significant amount of food that is wasted in developed countries is that consumers often expect visually suboptimal food as being less palatable. Using bananas as example, the objective of this study was to determine how appearance affects consumer overall liking, the rating of sensory attributes, purchase intention, and the intended use of bananas. The ripeness degree (RD) of the samples was adjusted to RD 5 (control) and RD 7 (more ripened, visually suboptimal). After preliminary experiments, a total of 233 participants were asked to judge their satisfaction with the intensity of sensory attributes that referred to flavor, taste, and texture using just-about-right scales. Subjects who received peeled samples were asked after tasting, whereas subjects who received unpeeled bananas judged expectation and, after peeling and tasting, perception. Expected overall liking and purchase intention were significantly lower for RD 7 bananas. Purchase intention was still significantly different between RD 5 and RD 7 after tasting, whereas no difference in overall liking was observed. Significant differences between RD 5 and RD 7 were observed when asking participants for their intended use of the bananas. Concerning the sensory attributes, penalty analysis revealed that only the firmness of the RD 7 bananas was still not just-about-right after tasting. The importance that consumers attribute to the shelf-life of food had a pronounced impact on purchase intention of bananas with different ripeness degree. In the case of suboptimal bananas, the results demonstrate a positive relationship between the sensory perception and overall liking and purchase intention. Convincing consumers that visually suboptimal food is still tasty is of high relevance for recommending different ways of communication.

Dairy-Based Emulsions: Viscosity Affects Fat Difference Thresholds and Sweetness Perception

In complex emulsions, viscosity or viscosity-associated sensory attributes such as creaminess are important for quality assessment and product differentiation. Two sets of emulsions with fat or locust bean gum content being varied at seven levels were developed; the two emulsions at each level had similar apparent viscosity. Additionally, sugar concentration was kept constant either with respect to total emulsion, or with respect to the aqueous phase. Series of two-alternative forced choice tests were performed with one constant stimulus, and just noticeable differences were calculated using probability regression. The results show that, when viscosity was not compensated, it was easy for the subjects to (a) distinguish emulsions with different fat content when the fat content was addressed in the question, and to (b) distinguish emulsions with different fat or locust bean gum content when creaminess was addressed. For the latter descriptor, it is of minor importance whether viscosity is altered by fat content or a thickener. Weber fractions that were calculated for viscosity were approximately 0.20. The quantitative effects of viscosity on sweetness, however, depend on how product rheology was modified.

Ultrasonic Cutting of Foods

In the field of food engineering, cutting is usually classified as a mechanical unit operation dealing with size reduction by applying external forces on a bulk product. Ultrasonic cutting is realized by superpositioning the macroscopic feed motion of the cutting device or of the product with a microscopic vibration of the cutting tool. The excited tool interacts with the product and generates a number of effects. Primary energy concentration in the separation zone and the modification of contact friction along the tool flanks arise from the cyclic loading and are responsible for benefits such as reduced cutting force, smooth cut surface, and reduced product deformation. Secondary effects such as absorption and cavitation originate from the propagation of the sound field in the product and are closely related to chemical and physical properties of the material to be cut. This chapter analyzes interactions between food products and ultrasonic cutting tools and relates these interactions with physical and chemical product properties as well as with processing parameters like cutting velocity, ultrasonic amplitude and frequency, and tool design.

Blackcurrant pomace from juice processing as partial flour substitute in savoury crackers: dough characteristics and product properties

Summary Berry pomace is a by-product of juice processing that, after drying and milling, may be used as an ingredient in cereal-based products. This, on the one hand, not only reduces losses of edible raw material components, but also increases the nutritional value of the target food because of its high dietary fibre and bioactive compounds content. By using savoury crackers as model, this study analyses how a partial flour replacement by blackcurrant pomace (levels: 10%, 20% or 30%) affects physical properties of the respective dough (dynamic rheology in simulated baking, extensibility and adhesiveness) and characteristics of the baked product (colour, texture and sensory properties). Pomace addition significantly affected both systems. By considering the high moisture absorption capacity of this material through water level adaptation in formulations and by only substituting gluten-free flour (which led to a constant gluten content), it is demonstrated that even a flour replacement of up to 30% leads to acceptable products. A restrained protein development was observed in pomace containing dough, leading to a lower extensibility, and to reduced volume increase and lower breaking force after baking. In contrast, dough handling and sensory acceptance were not corrupted by pomace application even though colour of the final product was changed to a great extent.