Determining optimum ripening time of fruits by applying survival analysis statistics to consumer data

When a consumer chooses a fruit like a tomato he or she can find it under-ripe, ok or over-ripe; leading to two events of interest: the transition of under-ripe to ok, and the transition of ok to over-ripe. The objective of the present work was to develop a methodology using survival analysis statistics to allow prediction of the optimum ripeness time based on acceptance or rejection data obtained from consumers. Concepts and calculations were applied to a data set obtained from 60 consumers who were asked to assess the appearance and the flavor of tomatoes picked at eight different ripening stages and answer whether they found the samples under-ripe, ok or over-ripe. The tomato at a time = 0 was completely green except for signs of initial redness at the tomato base, the tomato at a time = 7 days was completely red and with wrinkles on the outer surface. From the censored data set parametric models were obtained which allowed optimum ripeness time estimations and segmentation of consumers in groups according to whether they preferred more under-ripe or more over-ripe tomatoes. The optimum ripening times were 3.4 ± 0.7 days for appearance and 3.3 ± 0.8 days for flavor. These times were similar, but as ripening progressed tomato appearance was more important than flavor in the rejection of the fruit.     

Survival Analysis Applied to Sensory Shelf Life of Foods

ABSTRACT: Survival analysis concepts to be used in sensory shelf life studies were introduced, together with the equations necessary for calculations. The survival function was defined as the probability of consumers accepting a product beyond a certain storage time. Censoring phenomena, a key concept in survival analysis, was defined and has been shown to occur in sensory shelf‐life data. Concepts and calculations were applied to a data set obtained from 50 consumers who each tasted seven yogurt samples with different storage times, answering “yes” or “no” to whether they would consume the samples. From this censored data set, nonparametric and parametric models were obtained that allowed shelf‐life estimations.     

Effect of meat appearance on consumer preferences for pork chops in Greece and Cyprus

The effect of meat appearance on consumers’ preferences for pork chops was assessed using images manipulated for appearance characteristics. Data were collected from 412 consumers in Greece and Cyprus. Consumers were asked for their preference for pork chops from a book of computer-modified images and then completed a questionnaire of socio-demographic information, including eating and purchasing behaviour. Consumers under the age of 35 years showed preferences for dark red, lean pork, while consumers aged 35 years and older preferred either dark or light red pork. Gender appeared to be an important selection factor as men showed an increased preference for dark red pork while women preferred the light red. Consumers who stated that they like pork for its taste (91%) preferred either dark or light red pork chops while those who like pork for reasons other than taste preferred dark red, lean pork. Urban consumers preferred light red, fatty pork chops while the rural consumers preferred the dark red pork chops.     

Evolution of Quality Characteristics of Minimally Processed Asparagus During Storage in Different Lighting Conditions

ABSTRACT:  The effect of different types of lighting (white, green, red, and blue light) on minimally processed asparagus during storage at 4 °C was studied. The gas concentrations in the packages, pH, mesophilic counts, and weight loss were also determined. Lighting caused an increase in physiological activity. Asparagus stored under lighting achieved atmospheres with higher CO₂ and lower O₂ content than samples kept in the dark. This activity increase explains the greater deterioration experienced by samples stored under lighting, which clearly affected texture and especially color, accelerating the appearance of greenish hues in the tips and reddish-brown hues in the spears. Exposure to light had a negative effect on the quality parameters of the asparagus and it caused a significant reduction in shelf life. Hence, the 11 d shelf life of samples kept in the dark was reduced to only 3 d in samples kept under red and green light, and to 7 d in those kept under white and blue light. However, quality indicators such as the color of the tips and texture showed significantly better behavior under blue light than with white light, which allows us to state that it is better to use this type of light or blue-tinted packaging film for the display of minimally processed asparagus to consumers.     

CONSUMER ACCEPTABILITY OF COLOR IN PROCESSED TOMATO PRODUCTS BY AFRICAN-AMERICAN, LATINO AND PROTOTYPICAL CONSUMERS

African‐American, Latino, and Prototypical consumers rated the color of ketchup, salsa, tomato sauce, pizza sauce, spaghetti sauce, and barbecue sauce. For most products, ethnicity had little influence on acceptance. Prototypical consumers rated products the highest and had the widest preference range. All but one commercially available product was in the acceptable range, but they were not always in the most preferred range. Ketchup was the only product with no commercially available products in the color most preferred by Prototypical and African‐American consumers. The leading brand was within the most preferred range for all products and ethnic groups except African‐Americans and Prototypical consumers for ketchup and salsa. A peak color acceptance existed for all products: too red or too brown was undesirable. Understanding the optimum color range can help tomato processors increase the quality of their product for all consumers.     

Estimation of storage time of yogurt with artificial neural network modeling

Changes in the physical, chemical, and microbiological structure of yogurt determine the storage and shelf life of the product. In this study, microbial counts and pH values of yogurt during storage were determined at d 1, 7, and 14. Simultaneously, image processing of yogurt was digitized by using a machine vision system (MVS) to determine color changes during storage, and the obtained data were modeled with an artificial neural network (ANN) for prediction of shelf life of set-type whole-fat and low-fat yogurts. The ANN models were developed using back-propagation networks with a single hidden layer and sigmoid activation functions. The input variables of the network were pH; total aerobic, yeast, mold, and coliform counts; and color analysis values measured by the machine vision system. The output variable was the storage time of the yogurt. The modeling results showed that there was excellent agreement between the experimental data and predicted values, with a high determination coefficient (R² = 0.9996) showing that the developed model was able to analyze nonlinear multivariant data with very good performance, fewer parameters, and shorter calculation time. The model might be an alternative method to control the expiration date of yogurt shown in labeling and provide consumers with a safer food supply.     

Optimum Level of Salt in French‐Type Bread. Influence of Income Status,Salt Level in Daily Bread Consumption,and Test Location

ABSTRACT: The objectives of the present study were to measure the ideal salt concentration in French‐type bread among Argentine consumers in a home‐usage‐test (HUT) considering income status and salt content of daily bread consumption as covariables, and to compare the ideal salt concentrations measured in a HUT and a central‐location test (CLT). For the HUT, 420 consumers each received a sample of bread with a single salt concentration, and for the CLT, 100 consumers each received 7 samples with different salt concentrations. For each sample, consumers responded if they found the bread “not‐salty‐enough,”“okay,” or “too‐salty.” Neither income level nor salt content of daily bread influenced probability of rejection. The optimum sodium concentrations (milligrams per 100 g of bread dry basis) ± 95% confidence limits for the HUT and CLT were 980 ± 74 and 1157 ± 87, respectively. These values are substantially higher than 628, the mean sodium content of the bread sampled from the bakery shops where consumers bought their daily bread.     

Effects of mulberry pomace on physicochemical and textural properties of stirred-type flavored yogurt

Adding functional ingredients is an important method to develop functional dairy products. Mulberry pomace (MPo), a byproduct of mulberry fruit processing, is rich in phenolic compounds and anthocyanins and can be served as the functional ingredient in functional dairy products. The aim of this work was to prepare a functional flavored yogurt by incorporating MPo into stirred yogurt and to investigate the effects of MPo on the physicochemical and textural properties of the product during cold storage. We supplemented MPo powder up to 3% (wt/wt) in fermented milk, and the changes in color, pH, titratable acidity (TA), total phenol content (TPC), total anthocyanin content (TAC), water-holding capacity, rheological behavior, texture, and microstructure of the functional flavored yogurt were monitored during storage under 4°C for 28 d. The MPo powder brought a pink to dark red color to the yogurt, decreased the lightness (L*) and yellow-blue color (b*) values, increased the red-green color (a*) values, decreased the pH value, and increased the contents of TA, TPC, and TAC in a dose-dependent manner. The addition of MPo at 1%, 2%, and 3% (wt/wt) significantly increased water-holding capacity, consistency, viscosity, and viscosity index, and reduced firmness of yogurt samples. Supplementation of MPo significantly reduced the pore spaces and channels inside the samples and improved microstructure of the functional yogurt. During the 28 d of cold storage, MPo-fortified yogurt samples kept relatively constant color, although their L*, a*, and b* showed a decreasing tendency. The pH of all yogurt samples gradually decreased with increasing of TA. Interestingly, TPC and TAC contents and the texture parameters of MPo-fortified yogurt increased gradually and continuously during the 28 d of cold storage. Mulberry pomace is beneficial to improve the physicochemical and textural properties of yogurt and has the potential as a natural stabilizer to be used in functional yogurt rich in phytochemicals.     

Effect of illumination source on the appearance of fresh meat cuts

The effects of incandescent (INC), fluorescent (FL), and metal halide (MH) light sources on the appearance of fresh beef, pork and chicken meat were investigated. The color of all meats was more desired (P<0.05) when presented under an INC light source. The color used to describe beef meat presented under INC light was red, but dark brown or dark red under FL and MH. Relative luminance data, collected with a fiber optic probe connected to a photo diode array, demonstrated the reason to be a lack of redness in the commonly used FL and MH light sources. This difference was more pronounced in dark red beef cuts than in lighter pork and chicken cuts.     

Physico-Chemical Properties,Stability, and Potential Food Applications of Shrimp Lipid Extract Encapsulated by Complex Coacervation

Lipid extract from shrimp cephalothorax is a potential food coloring owing to its intense red color. However, it presents some drawbacks, such as its characteristic odor, astaxanthin instability, and difficult dosage and manipulation. The present work is an attempt to overcome these problems by means of complex coacervation encapsulation using gelatin and gum arabic as wall materials. Round molecules in which the lipid extract was efficiently encapsulated in the form of multiple droplets were obtained. The resulting microcapsules stabilized by freeze-drying had good properties with a view to their application as food coloring, owing to their intense red color, improved astaxanthin stability, and low water activity, water solubility, and hygroscopicity. The coloring capacity and sensory properties were evaluated when added to yogurt and a gellified fish product. For yogurt, a trained sensory panel determined that encapsulation effectively reduced the characteristic odor, whereas the coloring capacity was improved, as compared to non-encapsulated lipid extract. For the gellified fish product, no sensory improvement was observed, but the encapsulated lipid extract provided an attractive, uniform color.     

Satiety and consumers' perceptions: What opinions do Argentinian and Brazilian people have about yogurt fortified with dairy and legume proteins?

This study (1) evaluated the perceptions of Argentinian and Brazilian consumers regarding yogurt fortified with dairy proteins, legume proteins, or a combination of both, and (2) determined the satiety expectations of these foods as well as the consumers' intentions to taste and purchase protein-fortified yogurt. A total of 298 Argentinian and 100 Brazilian participants completed an online survey for this study. The free word association technique was used to investigate their perceptions about “satiety” as a verbal stimulus and 6 concepts of yogurt as visual/verbal stimuli (yogurt, set yogurt, skim set yogurt, skim set yogurt with a high content of dairy proteins, skim set yogurt with a high content of legume proteins, and skim set yogurt with a mix of dairy and legume proteins). The expected satiation and intentions to taste or purchase were evaluated using categorical scales. Regardless of their cultural background, participants from both countries expressed similar associations with the stimuli presented. Yogurt and set yogurt were associated with consumption occasions, sensory characteristics, liking, and foods, whereas skim yogurt was associated with diet food. Products fortified with proteins were associated with healthy foods, regardless of the protein source, and they yielded the highest rates for expected satiation. Brazilian participants were more likely to taste the food with a combination of proteins; however, participants from both countries were indifferent to purchasing the product. Important characteristics in the design and marketing of these products were pleasant sensations, such as “fullness,” “satisfied,” and snacks to eat “on the go,” and the vegetarian consumers' segment. The combination with fruits or cereals, creaminess, and vanilla flavor should also be considered. The study findings could have implications for the dairy industry when designing yogurt fortified with proteins and communicating the nutritional and wholesome properties of these products.     

Comparison of hydrodistillation methods for the deodorization of turmeric

The objective of this work was to investigate the influence of different hydrodistillation procedures on the deodorization of turmeric. Among the methods tested, distillation under high vacuum, using a Kjeldahl apparatus, and using a rotary evaporator were not viable or efficient. Distillation of medium size grated turmeric using a Clevenger apparatus for 4 h provided a powder with less residual turmeric flavor, without pigment loss and with similar color characteristics compared to a control and to turmeric deodorized with the solvent hexane. The deodorized and non-deodorized turmeric samples were used as natural colors in orange-flavored yogurt and passion fruit-flavored gelatin. No significant difference was observed for yogurt samples by sensory evaluation. However, the gelatin prepared with deodorized turmeric was preferred over the control. The deodorization of turmeric using the Clevenger method would allow a more widespread use in the food industry, including products in which the characteristic turmeric flavor is undesirable.     

Determination of color, pigment, and phenolic stability in yogurt systems colored with nonacylated anthocyanins from Berberis boliviana L. as compared to other natural/synthetic colorants

ABSTRACT:  Anthocyanins are of interest to the food industry because of their antioxidant power, attractive color, and stability in high acid foods. Powder from the Peruvian berry Berberis boliviana Lechler, rich in nonacylated anthocyanins (7% to 8% dry weight), was incorporated into yogurt samples containing 3 different fat levels. Color (CIE L , a , b , chroma, and hue angle), pigment (monomeric anthocyanin and polymeric color), and total phenolics were monitored over 8 wk of storage and compared to yogurt treatments containing purple carrot acylated anthocyanins, red beet betalaines, or FD&C Red nr 40. Anthocyanin profiles were analyzed by HPLC coupled to photodiode array and mass detectors. Color of yogurt containing B. boliviana anthocyanins at 20 mg cyanidin-3-glucoside (cy-3-glu) equivalents/100 g yogurt ( L *= 65, chroma = 14, and hue angle = 335°) was similar to commercial blueberry yogurt ( L *= 65, chroma = 10.5, and hue angle = 341°). High color, pigment, and phenolic stability were observed in yogurts colored with B. boliviana , independent of the fat matrix. Acylated anthocyanins from purple carrot extracts exhibited increased stability with higher fat content. Anthocyanin degradation followed 1st-order kinetics. Pigment half-lives were 125 and 104 d for nonacylated anthocyanins at 10 and 20 mg cy-3-glu equivalents/100 g yogurt and 550.2, 232.6, and 128.9 d for acylated anthocyanins at 20 mg of cy-3-glu equivalents/100 g of 4%, 2%, and 0% fat yogurt. Addition of B. boliviana whole berry powder to yogurt matrices produced an attractive, stable anthocyanin-rich product, eliminating the need for industrial colorant extraction.     

IDENTIFICATION OF SENSORY COLOR OPTIMA OF STRAWBERRY YOGURT

Commercially available strawberry yogurts were subjected to preference ranking done by an untrained panel and to instrumental color analysis. Spectral reflectance data and color values expressed in the CIELAB system revealed different color properties of the yogurts, mainly with respect to the hue angle determining whether a product is, e.g., dominantly red or dominantly orange. Sensory evaluations resulted in three groups of products being significantly different from each other with respect to their preference patterns. The tomato color index originally proposed for measuring the ripening index of tomatoes appeared to be useful to reduce 3‐dimensional yogurt color values to one dimension and to construct a function of preference ranks versus instrumentally measured data.     

Acceptance of sugar reduction in flavored yogurt

To investigate what level of sugar reduction is accepted in flavored yogurt, we conducted a hedonic test focusing on the degree of liking of the products and on optimal sweetness and aroma levels. For both flavorings (strawberry and coffee), consumers preferred yogurt containing 10% added sugar. However, yogurt containing 7% added sugar was also acceptable. On the just-about-right scale, yogurt containing 10% sugar was more often described as too sweet compared with yogurt containing 7% sugar. On the other hand, the sweetness and aroma intensity for yogurt containing 5% sugar was judged as too low. A second test was conducted to determine the effect of flavoring concentration on the acceptance of yogurt containing 7% sugar. Yogurts containing the highest concentrations of flavoring (11% strawberry, 0.75% coffee) were less appreciated. Additionally, the largest percentage of consumers perceived these yogurts as “not sweet enough.” These results indicate that consumers would accept flavored yogurts with 7% added sugar instead of 10%, but 5% sugar would be too low. Additionally, an increase in flavor concentration is undesirable for yogurt containing 7% added sugar.     

Consumer preferences for the color of unprocessed animal foods

Consumer choices for food products are often based on appearance; one important aspect being product color. We systematically review the literature on consumer preferences for the color of raw beef, pork, poultry, bee honey, cow milk, and chicken eggs to inform future food technology and marketing research; a total of 40 studies were identified. Consumer preferences for pork color vary widely globally and can depend on other demographic factors. A trend toward light and bright beef was observed in six out of eight studies. A pink color was preferred in chicken by consumers in Northern Ireland and Brazil; muscle color uniformity was also related to higher acceptance. Contrarily, a diverse selection of honey colors is preferred; dark golden, yellow, and amber products were liked by consumers across the globe. One study observed a preference for white (over yellowish) milk. Worldwide, white and brown eggshells are preferred nearly equally with considerable differences between continents and regions. Our review highlights the heterogeneity of color preferences for animal products, worldwide; research methods should focus on quantifying colors associated with preferences so that food producers can accurately market their diverse products in regions with corresponding color preferences.     

International preferences for pork appearance: I. Consumer choices

Using the same digital photographs of pork chops varying systematically in fat cover, colour, marbling and drip, 12,590 consumers from 23 countries each selected their preferred chop. Preferences differed considerably between individuals, between groups and between countries when comparing equivalent subsets of consumers taken from each country. Most choices were based on two appearance characteristics. Overall, both dark and light red pork were preferred equally and often with low fat cover. Preference for the light red pork was frequently chosen in association with no drip. Low fat cover was preferred by the majority of consumers, particularly in Poland, Finland and Mexico. Strong characteristic pork preferences were given by consumers in Ireland (the majority preferring light red, lean, no marbling and no drip), Australia (light red, lean, no marbling), Korea (marbled), Taiwan (dark red and lean) and Poland (lean). Effective marketing of pork should respond to the differing consumer preferences.     

不同因素对冷鲜牛肉肉色变化的影响

以冷鲜牛肉为原料,研究了保鲜膜、细菌和光照对肉色变化的影响。原料肉块分别进行PE膜包装及不包装,4℃贮存1 20h,测定其L、a、b值,并观察各组颜色变化;无菌条件下,分别接种荧光假单胞菌和植物乳杆菌于经处理的原料肉浸提液中,30℃封闭遮光培养,测定各组的MetMb%值,并观察颜色变化;选用避光、白光、红光和蓝光分别照射经处理的原料肉块,4℃贮存120h,测定其a值。结果表明,PE膜包装组及不包装组,4℃贮存120h,其a值均下降,感官评定两者不存在显著性差异(P>0.05);在培养初期,荧光假单胞菌可促进肉色变暗,乳酸菌能延缓肉色变化;4C贮存下,避光、白光及红光对肉色变化的影响之间不存在显著性差异,但蓝光能明显加快牛肉变色。     

The adaptive eater: Perceived healthiness moderates the effect of the color red on consumption

Previous studies suggest that the color red reduces food intake because it signals danger and hence acts as a consumption-stopping cue. We demonstrate that this effect cannot be generalized to just any kind of food. Consequently, we show that the color red—despite eliciting similar associations—affects behavior more strongly with regard to unhealthy (potentially harmful) food compared to healthy food. Specifically, the color red more strongly influenced the amount of unhealthy food intake (Study 1) and the choice of unhealthy food options (Study 2) compared to healthy food. Study 2 further demonstrated that the impact of color on behavior decreases gradually as food options become healthier. Moreover, the effect can be observed for subtle (Study 1) as well as salient (Study 2) color cues. These results suggest that consumers do not react in a generalized but in an adaptive way to the color red.     

DISPLAY LIGHT AND ACCEPTABILITY OF GREEN, RED AND YELLOW PEPPERS

The effects of incandescent (INC), fluorescent (FL), and metal halide (MH) light sources on the appearance of red, green, and yellow sweet bell peppers were investigated. The color of the red pepper was significantly preferred when presented under INC than under FL and MH lights. The term used by the panelists to describe the color of peppers under INC light was mainly bright red, but dark red under FL and MH. Relative luminance data, collected with a fiber optic probe connected to a photo diode array, demonstrated the reason to be the low red light output from the FL and MH sources, which resulted in a low visible red color. The color of the green pepper was more acceptable under INC than under MH. For the yellow pepper, there was no significant effect of the light source because all three light bulbs emit a strong yellow component.