Application of ultrasound and microencapsulation on Limosilactobacillus reuteri DSM 17938 as a metabolic attenuation strategy for tomato juice probiotication

Counteracting probiotic-induced physicochemical and sensory changes is a challenge in the development of probiotic beverages. The aim of the study is to apply ultrasound and microencapsulation for the attenuation of Limosilactobacillus reuteri DSM 17938 to avoid change in a probiotic tomato juice. Preliminarily, six ultrasound treatments were applied. Probiotic survival in acid environment (pH 2.5) and bile salts (1.5 g/l) after ultrasound treatment was also studied. The probiotic was inoculated in tomato juice in four forms: free cells (PRO-TJ), sonicated-free cells (US-TJ), untreated-microencapsulated (PRO-MC-TJ) and sonicated-microencapsulated cells (US-MC-TJ). Probiotic viability and pH were monitored during 28 days of storage at 4 and 20 °C. Sensory analysis was performed for PRO-TJ and US-MC-TJ sample (4 °C). Ultrasound (57 W for 6 min) did not affect cell survival and transitorily modulated probiotic acidifying capacity; it reduced probiotic survival in acidic environment but increased probiotic survival in bile salts solution. Ultrasound was effective in maintain pH value of tomato juice but only at 4 °C. Instead, microencapsulation with sodium-alginate leads to a more stable probiotic juice, particularly at 20 °C. Finally, probiotication slightly modified some sensory attributes of the juice. This study shows the potential of ultrasound and microencapsulation as attenuation strategies and highlights the need for process optimization to increase ultrasound efficacy

Anti-Adhesion Elastomer Seal Coatings for Ultraviolet and Atomic Oxygen Protection

Radiation blocking sunscreen coatings have been developed for the protection of elastomer seals used in low-Earth-orbit (LEO). The coatings protect the seals from ultraviolet (UV) radiation and atomic oxygen (AO) damage. The coatings were developed for use on NASA docking seals. Docking seal damage from the UV and AO present in LEO can constrain mission time-line, flight mode options, and increases risk. A low level of adhesion is also required for docking seals so undocking push-off forces can be low. The coatings presented also mitigate this unwanted adhesion. Greases with low collected volatile condensable materials (CVCM) and low total mass loss (TML) were mixed with slippery and/or UV blocking powders to create the protective coatings. Coatings were applied at rates up to 2 milligrams per square centimeter. Coated seals were exposed to AO and UV in the NUV (near-UV) and UV-C wavelength ranges (300 to 400 nanometers and 254 nanometers, respectively). Ground based ashers were used to simulate the AO of space. The Sun's UV energy was mimicked assuming a nose forward flight mode, resulting in an exposure rate of 2.5 megajoules per square meter per day. Exposures between 0 and 147 megajoules per square meter (UV-C) and 245 megajoules per square meter (NUV) were accomplished. The protective coatings were durable, providing protection from UV after a simulated docking and undocking cycle. The level of protection begins to decline at coverage rates less than 0.9 milligrams per square centimeter. The leakage of seals coated with Braycote plus 20 percent Z-cote ZnO sunscreen increased by a factor of 40 after moderate AO exposure; indicating that this coating might not be suitable due to AO intolerance. Seals coated with DC-7-16.4 percent Z-cote ZnO sunscreen were not significantly affected by combined doses of 2 x 10 (sup 21) atoms per square AO with 73 megajoules per square meter UV-C. Unprotected seals were significantly damaged at UV-C exposures of 0.3 megajoules per square meter and DC-7-16.4 percent Z-cote coated seals were undamaged at all exposures up to the limits tested thus far which were 147 megajoules per square meter UV-C and 245 megajoules per square meter NUV. The coatings decreased adhesion sufficiently for docking seals at temperatures equal to or greater than -8 degrees Centigrade thus offer a simple and inexpensive way to mitigate adhesion

Food neophobia, odor and taste sensitivity, and overall flavor perception in food

Smell, which allows us to gather information about the hedonic value of an odor, is affected by many factors. This study aimed to assess the relationship among individual factors, odor sensitivity, and enjoyment, and to evaluate how overall flavor perception and liking in actual food samples are affected by odor sensitivity. A total of 749 subjects, from four different Italian regions, participated in the study. The olfactory capabilities test on four odors (anise, banana, mint, and pine), as well as PROP (6-n-prpyl-2-thiouracil) status and food neophobia were assessed. The subjects were clustered into three groups of odor sensitivity, based on the perceived intensity of anise. The liking and intensity of the overall flavor were evaluated for four chocolate puddings with increasing sweetness (C1, C2, C3, and C4). The individual variables significantly affected the perceived intensity and liking of the odors. Even if all of the odor sensitivity groups perceived the more intensely flavored samples as the C1 and C4 chocolate puddings, the high-sensitivity group scored the global flavor of all of the samples as more intense than the low-sensitivity group. The low-sensitive subjects evaluated the liking of the sweeter samples with higher scores than the moderate-sensitive subjects, whereas the high-sensitive subjects gave intermediate scores. In conclusion, odor sensitivity plays a pivotal role in the perception and liking of real food products; this has to be taken into account in the formulation of new products, suitable for particular categories with reduced olfactory abilities

Texture and trigeminal sensations: new approaches to measure the human sensitivity

Food preference and choice are affected by many interacting factors in humans. These variables are related to the food (taste, odour, texture etc.), to the consumer (biological, physiological, psychological and attitudinal factors) and to the external context. Among the consumer variables, sensory sensitivity plays a pivotal role in food preference and choice. Several methods have been validated to measure the taste and odor sensitivity and the relationships with food preferences and choice have been largely investigated. However, besides tastes and odour, texture and trigeminal sensitivities, and how they could affect food rejection or preferences and choice, is poorly investigated. The reason why little is known about texture and trigeminal sensations is a missing standardized procedure to measure the individual sensitivities, which uses real food products or food ingredients. The aim of this PhD thesis was to develop a new approach to measure the individual sensory sensitivities to specific key attributes, varied in different levels of intensity, by conducting four cases study. Simultaneously, the effect of individual sensitivities on food preference and choice was also investigated. The first case study aimed to develop the method to measure the texture sensitivity, using the graininess as key-texture attribute. To this purpose, cocoa-based creams with different levels of graininess were instrumentally characterized and evaluated by the consumers in terms of perceived graininess and liking. Data showed that using the instrumental characterization to predict the individual sensitivity allows clustering people according to their ability to discriminate different levels of graininess. The second case study aimed to validate the approach used in the first one, using a larger sample of consumers and measuring the sensitivity to the hardness, as key-texture attribute. To this purpose, different jellies were developed by changing the concentration of the gelling agent, in order to obtain different levels of hardness. Results confirmed that the developed statistical methodology can be used to measure the sensitivity to any texture attribute that can be first analysed by means of instruments. Also, individual characteristics, such as gender and age, showed to play an important role in hardness perception and food liking. The third case study aimed to use the approach developed in the first case study and validated in the second one, to explore the role of the sensitivity to viscosity on food choice. According to the aim, several pastry choco-creams were made by using different solid/liquid ratios, in order to obtain different viscosities. After clustering people in three groups of sensitivity, a food choice index was calculated from the Food Choice questionnaire developed on the basis of texture dichotomies. Data showed that, first, once again, the proposed method is reproducible and can be used to measure the sensitivity to viscosity as well. Secondly, different sensitivities led to different preferences and different texture choices. Finally, the last case study aimed to explore the sparkling sensation, used as key-trigeminal attribute, in order to determine how detection thresholds for and perception of sparkling sensations in carbonated mineral water are affected by familiarity with carbonated beverages and individual consumer characteristics. Data collected from consumers showed that detection thresholds of sparkling sensations are independent of consumption behaviour and preferences for carbonated beverages. On the other hand, liking and perception of sparkling intensity of carbonated mineral water were significantly affected by the consumption frequency of sparkling water. In conclusion, differences in texture and trigeminal perception exist, the proposed methods are valid to measure them and the statistical approach is useful to cluster the people with different sensitivities Also, individual characteristics, such as gender, age and consumption behaviour, play an important role in individual sensitivities and food liking

Oral Sensitivity to Flowability and Food Neophobia Drive Food Preferences and Choice

The study aimed to investigate the role of sensitivity to flowability on food liking and choice, the relationship between sensitivity to flowability and food neophobia, and its role in food liking. Five chocolate creams were prepared with different levels of flowability, and rheological measurements were performed to characterise them. One hundred seventy-six subjects filled in the Food Neophobia Scale and a food choice questionnaire (FCq). The FCq was developed to evaluate preferences within a pair of food items similar in flavour but different in texture. Secondly, the subjects evaluated their liking for creams (labelled affective magnitude (LAM) scale) and the flowability intensity (generalised labelled magnitude (gLM) scale). The subjects were clustered into three groups of sensitivity and two groups of choice preference. The effect of individual flowability sensitivity on food choice was investigated. Finally, the subjects were clustered into two groups according to their food neophobia level. The sensitivity to flowability significantly affected the liking of chocolate creams and the solid food choice. The liking of chocolate creams was also affected by the individual level of neophobia (p = 0.01), which, in turn, was not correlated to flowability sensitivity. These results confirm that texture sensitivity and food neophobia affect what a person likes and drives what a person chooses to eat

Is it still water? Relationships between sparkling sensitivity and consumption frequency of carbonated waters

Little is known about how sensitivity to trigeminal stimulation such as carbonation is affected by consumption habits and consumer characteristics. The aim of this study was to determine how detection thresholds for and perception of sparkling sensations in carbonated mineral water are affected by frequency of consumption of carbonated water and individual consumer characteristics. One hundred subjects differing in sparkling water consumption frequency (non-consumers, infrequent consumers, frequent consumers) participated. First, sparkling sensation detection thresholds were determined using the method of best estimate threshold (BET) with CO2 concentrations ranging from 0.03 to 1.05 g/L. Secondly, intensity of sparkling sensation and liking of five sparkling waters (CO2 concentrations ranging from 0.21 to 4.92 g/L) were assessed. To characterize consumers, consumption frequency of sparkling water, sensitivity to 6-n-propylthiouracil (PROP taster status) and consumer characteristics were determined. Average detection threshold of sparkling sensation (BET) was 0.44 g/L CO2 concentration. BET of sparkling sensation was not affected by consumption frequency of sparkling water and was not related to PROP taster status and consumer characteristics. Perception of sparkling intensity and liking of carbonated mineral water were significantly affected by consumption frequency of sparkling water. Sparkling sensations were perceived significantly more intensive by non-consumers compared to infrequent and frequent consumers. Surprisingly, non-consumers liked sparkling water significantly more than infrequent or frequent consumers. We conclude that consumption frequency of and preferences for carbonated water do not influence detection thresholds of sparkling sensations but influence suprathreshold intensity perception of sparkling sensations in carbonated water

How sensory sensitivity to graininess could be measured?

Considering the lack of the literature and the need for developing a valid method to measure the texture sensitivity, in this study, we investigated the individual sensitivity to discriminate among different levels of graininess. With this purpose, five samples of cocoa-based creams were prepared, by changing the refining time. Samples were first characterized in terms of particles size distribution, by means of laser diffraction. Then, 59 subjects evaluated the cream sample graininess intensity, by using gLM scales, and their liking, by using LAM scales. The graininess scores of each subject were fitted with a power model, already observed with the instrumental results, estimating both the power law exponent and the R2 coefficient, and using them as clustering parameters. Subjects were then clustered into three groups: high sensitivity; moderate sensitivity; low sensitivity. First, as it was hypothesized, results showed a significant difference between the three groups in terms of perceived graininess. Second, even though results showed a significant difference between the three groups in terms of perceived graininess, only little differences were found in terms of liking scores. Indeed, all the samples were equally liked for both the moderate and low sensitivity groups, whereas a significant trend was observed for the highly sensitive subjects who liked more the most refined samples. No significant relationships were found with age, and only a little trend was observed with gender: females seemed to be more sensitive than males. Texture attributes discrimination ability, as for example sensitivity to graininess, could affect food rejection or preferences and choice, but it is poorly investigated. This exploratory study, proposes a method to cluster consumers, based on their sensitivity. A statistical methodology has been developed to discriminate among consumer sensitivity levels. The results provide useful information about graininess sensitivity suggesting that the used methodologies could be applied to other texture properties resulting in a valid tool for the industry in the development and optimization of tailored new products

Sensory evaluation and volatile compounds of an alternative ready-to-use therapeutic food for malnourished children.

Ready-to-use therapeutic foods (RUTFs) are special foods used to encourage rapid weight gain in 5-year-old malnourished children, avoiding hospitalization. The factors affecting sensory characteristics and acceptability of RUTFs have been not adequately described. The aim of this work was to evaluate both the sensory properties and volatile compounds of four alternative RUTFs, varying in soy and sorghum, icing sugar, and oil content. Nine nonoral sensory attributes were evaluated by nine selected and trained assessors. The perceived intensity of five oral sensory attributes and the overall liking were assessed by 100 adult consumers. The volatile compounds were extracted and concentrated by solid phase microextraction and analyzed by gas chromatography/mass spectrometry. RUTF formulations significantly differed for graininess between fingers (size of granules) (P = 0.007), viscosity (P = 0.013), adhesiveness to the spoon (P < 0.044), and meltability (P = 0.005), but in consumers’ opinion, they differed only for difficulty in swallowing, intensity of global odor, flavor, and sweetness. A positive correlation between overall liking and sweetness was found. Volatile compounds arising from lipid oxidation (hexanal and octanoic acid) were positively correlated with global odor and flavor. These attributes negatively affected the overall liking and were mainly contained in one out of the four formulations. Sensory and instrumental characterization identified key attributes for this kind of food, such as difficulty in swallowing, global odor, and sweetness, suggesting how to formulate an alternative RUTF to be used for a future clinical trial on malnourished children

Pungency perception and liking for pasta filata cheeses in consumers from different Italian regions

We aimed to investigate whether the sensitivity to capsaicin had an effect on pungency perception of pasta filata cheeses. In addition, we assessed the effect of several individual variables (gender, age, consumer provenance, PROP status and personality traits) on both consumer liking and choice for pasta filata cheeses. Four pasta filata cheeses at two ripening times and 272 subjects from three different Italian locations were used. Based on sensory data, the PCA discriminated sweet (ripened at 2 months) from pungent cheeses (ripened at 12 months). Cheese pungency perception increased with increasing sensitivity to capsaicin (P < 0.001). There was no clear relationship between sensitivity to capsaicin or sensitivity to cheese pungency with cheese liking, whereas a number of other aspects, including sensory attributes and individual consumer characteristics, such as consumer provenance (P < 0.001), gender (P < 0.001) and food neophobia (P < 0.05), affected the liking for different pasta filata cheeses. Consumers who were younger (18–30 y.o.; P < 0.05), female (P < 0.001), unfamiliar with pungent foods (P < 0.0001) and consumers from Potenza (P = 0.001) more often declared to prefer sweet over pungent cheese, whereas in terms of real choice supertasters and neophobic subjects chose the sweet option more often (P = 0.01). In conclusion, sensitivity to capsaicin affected pungency perception in pasta filata cheese, whereas no clear relationship was observed between pungency perception and liking. The contribution of cheese and consumer characteristics on cheese liking and choice in addition to pungency, was confirmed by the differences in declared and real choice for sweet or pungent cheeses