Neutral Flavor Research Articles

The nature of training in flavor preference learning determines the underlying associative structure

Pairing a palatable flavor (US) with an initially neutral flavor cue (CS) results in an acquired conditioned preference for the latter. Two main associations have been proposed to explain the acquisition of flavor preferences: Flavor-Flavor and Flavor-Nutrient learning. Although the hedonic reaction triggered by US consumption has also been suggested as a possible additional component underlying acquired flavor preference, this issue has received little attention. Here we explored whether the amount of training to the CS-US compound can favor the formation of a Flavor-Hedonic reaction association using rats as subjects and sucrose as the US. We expected that the more exposure to the CS-US compound, the stronger the S-R type association. Since S-R associations are not sensitive to devaluation procedures, we used a Sensory-Specific Satiety procedure to devalue the US after conditioning and then measured preferences for the CS. On Experiment 1 with a short restrictive training (classic procedure), preference for the CS was decreased after devaluation of the US compared to the control condition. On Experiment 2, with short unrestrictive training, preference for the CS was again weakened. Experiment 3 with a long unrestrictive training, rats expressed preference for the CS regardless of the devaluation procedure. These results suggest that, as with an instrumental paradigm, extensive training in flavor preference learning undermines the US devaluation effect.

Salivary proteins rescue within-session suppression and conditioned avoidance in response to an intragastric quinine infusion

A subset of salivary proteins (SPs) upregulates in response to a quinine-containing diet. The presence of these SPs then results in decreased bitter taste responding and taste nerve signaling. Bitter taste receptors in the oral cavity are also found in the stomach and intestines and contribute to behaviors that are influenced by post-oral signaling. It has been previously demonstrated that after several pairings of post-orally infused bitter stimuli and a neutral flavor, animals learn to avoid the flavor that was paired with gastric bitter, this is referred to as conditioned avoidance. Furthermore, animals will decrease licking of a neutral solution within a test session, when licking is paired with an intragastric bitter infusion; this has been described as within-session suppression. We used these paradigms to test the role of SPs in behaviors influenced by post-oral signaling. In both paradigms, the animal is given a test solution directly into the stomach (with or without quinine, and with or without SPs), and the infusions are self-administered by licking to a neutral solution (Kool-Aid). Quinine successfully conditioned a flavor avoidance, but, in a separate trial, we were unable to detect conditioning in the presence of SPs from donor animals. Likewise, quinine was able to suppress licking within the conditioned suppression paradigm, but the effect of the bitter was blocked in the presence of saliva containing SPs. Together, these data suggest that behaviors driven by post-oral signaling can be altered by SPs.

Enhancing the aroma of white whole sorghum flour using supercritical carbon dioxide

Removal of undesired odor-active compounds from sorghum flour is vital for the widespread production of sorghum-based foods. This study investigated the use of supercritical carbon dioxide (SCCO2) for the extraction of volatile compounds (VCs) from white sorghum flour. The extraction temperature (33.18–66.81 °C), pressure (8.18–41.82 MPa), and time (1.32–4.68 h) were optimized for the removal of 11 VCs (decane, undecane, tetradecane, dodecane, hexanal, nonanal, hexanol, dodecanol, limonene, styrene, and butylated hydroxytoluene) from whole white sorghum flour using a central composite response surface design. The maximum VC removal (∼89%) was obtained at 60 °C and 15 MPa with 2 h extraction time. SCCO2 extraction at higher pressures (> 15 MPa) or lower temperatures (<60 °C) did not improve the VC removal. After SCCO2 treatment, water absorption index, oil absorption capacity, and swelling power increased, whereas moisture/lipid contents, water solubility index, and particle size reduced significantly (p<0.05). The lightness of the sorghum flour treated with SCCO2 increased significantly compared to untreated sorghum flour, while the yellowness decreased after SCCO2 extraction (p<0.05). Overall, this study developed a novel green approach to enhancing the aroma of sorghum flour, which has a high potential for scale-up, and generating sorghum flours with more neutral flavors for numerous food applications.

Transverse proton gluon anisotropy points behind the Standard Model

The present work focuses on transverse gluon densities in the proton and derives exemplar distributions showing azimuthal anisotropies. Such anomalies relative to the Standard Model may be visible in scattering experiments involving protons. I describe baryons as mass eigenstates of a Hamiltonian structure on an intrinsic U(3) configuration space. This has yielded the neutral flavour baryon spectrum and given a rather accurate value for the neutron mass 939.9(5) MeV from first principles. Quark and gluon fields are shaped by the momentum form of the intrinsic wave function. This has led to parton distribution functions for the u and d valence quarks for the proton and to a proton spin structure function agreeing with experiments over four orders of magnitude in the parton momentum fraction.

Effects of Bacillus subtilis subsp. on the microbial community and aroma components of flue-cured tobacco leaves based on metagenome analysis.

To improve the sensory quality of aged flue-cured tobacco (FCT), Bacillus subtilis subsp, H11 was inoculated on aged FCT leaves named Pingdingshan DCFB. The metagenome and thecharacteristic aroma substances of aged FCT with different fermentation times (0h, 12h, 24h, and 36h) were systematically analyzed. The results showed that the content of aroma components and sensory quality of aged FCT were significantly improved when the strain was treated at 35°C with 25% moisture for 24h. The inoculation of H11 had a strong influence on the microbial composition and metabolism of the aged FCT leaf surface. Five microorganisms Pantoea (35.04%, 20.12-56.95%), Enterobacter (22.16, 13.60-39.82%), Pseudomonas (12.12, 3.13-26.17%), Terribacillus (8.00%, 4.65-13.01%) and Bacillus (6.54%, 0.67-16.96%) accounted for the largest proportion during the process of fermentation. The content of most neutral flavor components such as ketones and aldehydes in FCT after fermentation was higher than that priorto fermentation. After 24h fermentation, 3-furfural, 5-methylfurfural, dihydrokiwi lactone and megalotrienone increased by 71.42%, 49.19%, 21.09%, and 10.56%, respectively. Correlation analysis between groups showed that Pseudomonas was significantly correlated with (E, E)-2, 4-heptadienal (P < 0.05), Franconibacter was correlated with damascus ketone (P < 0.05), and Terribacillus was related to the production of β-citral (P < 0.05). GH9 may be involved in the formation of damasone (P < 0.05), and 4-cyclopentene-1, 3-dione was significantly correlated with glycoside hydrolase family 5 (GH5) (P < 0.05). The correlation between 4-oxyisophorone and GH31, GH103, GH73, and GH3 was significant (P < 0.05). Microorganisms and GHs may play important roles in FCT fermentation.

PHYSICAL, CHEMICAL, AND ORGANOLEPTIC CHARACTERISTICS OF RICE ANALOG MADE FROM MOCAF, CORN FLOUR (Zea mays L.), AND MUNG BEAN SPROUT FLOUR (Vigna radiata L.)

The food intake of Indonesian people includes a typically high amount of rice . However, the domestic production of rice has not fulfilled the needs. Therefore, a rice analog whose characteristics resemble rice could be an alternative rice substitute . The rice analog discussed in this study was made from a combination of mocaf, cornflour, and mung bean sprout flour. The study aimed to discover the effect of different combinations of the three main ingredients on rice analog's chemical and physical characteristics, to obtain the best formulation based on sensory evaluation, and to evaluate its chemical and physical properties . This study began with the manufacture of mung bean sprout flour and then the manufacture of rice analog . This study was conducted by completely randomized design (CRD) with a ratio between mocaf and mung bean sprout flour as the single factor. The 5 formulas to be assessed were F1 (50%:10%), F2 (40%:20%), F3 (30%:30%), F4 (20%:40%), F5 (10%:50%). A s ensory evaluation was conducted by the hedonic test scoring method. Based on sensory evaluation, formula F1 that was composed of 50% mocaf, 40% corn flour, and 10% mung bean sprout flour was the best formulation among all. This formula had a yellowish-white color, hulled rice-like oval and long shape, insipidity, neutral flavor, and sticky texture. The rice analogue F1’s chemical characteristics included 7.301% water content (wb), 1.284% ash content (db), 6.513% fat content (db), 6.694% protein content (db), 75.198% carbohydrate content (db), 23.365% amylose content, and 13.164% antioxidant content. Based on physical analysis, this rice analog had color value 76.208 °Hue (yellow-red colors), weight per grain 0.027g, bulk density 0.556 g/ml, water absorption 118%, cooking time 7.222 minutes, and swelling power 27.254%.

Preferences of Sjögren’s syndrome patients regarding potential new saliva substitutes

ObjectivesSjögren’s syndrome (SS) patients should be involved in the development of new saliva substitutes at an early stage. The purpose of the current study was to explore the preferences of these patients regarding various product characteristics of potential new saliva substitutes.Material and methodA questionnaire was distributed among SS patients. They could anonymously indicate their preferences for saliva substitute characteristics using 5-point Likert scales.ResultsFifty-nine SS patients filled in the questionnaire. According to their opinion, the most ideal saliva substitute has a thin-watery consistency with a neutral flavour that should be applied as a spray. Patients demand a prolonged alleviation of dry mouth complaints and neutralization of harmful bacteria. The patients mainly object against the presence of artificial sweeteners and alcohol in saliva substitutes, but have limited objections against the presence of vegetable-based ingredients and natural enzymes. Major objections were against the potential side effects “bitter taste” and “discoloration of teeth”. Age and severity of xerostomia affected desire of flavours. Younger patients preferred menthol flavour, while respondents with severe xerostomia preferred the use of “neutral flavours” significantly more.ConclusionThe most ideal saliva substitute has thin-watery consistency in spray form with a neutral flavour and providing long alleviation of dry mouth complaints. Besides, it should not contain artificial sweeteners or alcohol, and should not have a bitter taste or cause discoloration of the teeth.Clinical relevanceInvestigating the opinion of SS patients provides tailoured insights into their preference, which may contribute to the development of more effective saliva substitutes.

Rats learn to prefer the late-consumed flavor over the early-consumed flavor in a multi-flavored meal paired with oral glucose and corn oil

Conditioned flavor preference (CFP) is established by association: where a neutral flavor (conditioned stimulus, CS) is paired with orosensory and post-ingestive components of nutrients, including sugar and fat (unconditioned stimulus, US). A previous study reported that rats can learn to prefer flavors that they consumed earlier and later in a multi-flavored solution paired with an intragastric infusion of glucose, but they expressed only a preference for a late-consumed flavor when they were tested after feeding (Myers and Whitney, 2011). This paradigm can be a suitable rodent model to explain how humans acquire a selective preference for routinely late-served “dessert” foods and why these foods remain attractive even in the absence of hunger. Here, we examined whether oral glucose (Experiment 1) or fat (Experiment 2) acts as a US for flavor preference learning processes in this paradigm. In Experiment 1, adult female rats under food restriction were trained in 16 daily sessions with two distinct flavor CSs in succession per session; eight CS(+) sessions in which two distinct flavor CSs (early(+), late(+)) were sequentially presented for 8 min each with oral glucose (12%) as a US, and eight CS(-) sessions in which different CSs (early(-), late(-)) were unpaired with the US. In the 30-minute two-bottle choice test, rats preferred late(+) over late(-) only when tested 90 min after consumption of normal chow (fed test) but not after overnight deprivation (hungry test). Early(+) was not preferred over early(-) in both tests. Moreover, a significant preference for late(+) over early(+) was observed only in the fed test, which is a unique feature of oral glucose-CFP. These results indicate that taste sensations of oral glucose promote a rewarding effect of late-onset glucose nutrients. In Experiment 2, separate rats were trained with the same conditioning paradigm, but used a caloric matched fat solution (5.3% corn oil) for a US. The results showed that they expressed stronger preferences for early(+) and late(+) relative to their respective CS(-) flavors in both tests. Similar to Experiment 1, it was observed in the fed test that there was a preference for late(+) over early(+) in oral fat-CFP. Taken together, the present results suggest that routine timing arrangements can cause qualitative differences in conditioned preferences between multiple flavors within a sugar or fat-containing meal in rats, and that rats prefer the late-consumed flavor over the early-consumed flavor in the absence of hunger.

Transverse positron polarization in the polarized μ+ decay related with the muonium-to-antimuonium transition

The constructions of the new high-intensity muon beamlines are progressing in facilities around the world, and new physics searches related to the muons are expected. The facilities can observe the transverse positron polarization of the polarized ${\ensuremath{\mu}}^{+}$ decay to test the standard model. The transition of muonium into antimuonium (Mu-to-$\overline{\mathrm{Mu}}$ transition), which is one of the interesting possibilities in the models beyond the standard model, can be also tested. An observation of the transition in the near future would have a great impact since it would indicate that there is an approximate discrete symmetry in the lepton sector. If the Mu-to-$\overline{\mathrm{Mu}}$ transition operator is generated, a new muon decay operator can exist, and it may interfere with the standard model muon decay operator to induce the corrections to the transverse positron polarization in the ${\ensuremath{\mu}}^{+}$ decay. We examine the possibility that the Mu-to-$\overline{\mathrm{Mu}}$ transition and the correction to the transverse positron polarization are related, and we show that the two are related in the model of a neutral flavor gauge boson. We also investigate the models to generate the Mu-to-$\overline{\mathrm{Mu}}$ transition, such as an inert $SU(2{)}_{L}$ doublet, an $SU(2{)}_{L}$ triplet for the type-II seesaw model, a dilepton gauge boson, and a left-right model. The nonzero value of the transverse polarization for one of the two directions, ${P}_{{\mathrm{T}}_{2}}$, violates the time-reversal invariance, and the experimental constraint of the electron electric dipole moment can provide a severe constraint on ${P}_{{\mathrm{T}}_{2}}$, depending on the model.

Ultrasound-Assisted Extraction and Characterization of Polyphenols from Apple Pomace, Functional Ingredients for Beef Burger Fortification.

Currently, there is an increasing interest to valorise agri-food waste containing bioactive compounds with potential health benefits. In this paper, the recovery of functional molecules from apple pomace, the most abundant by-product of the apple processing industry, was carried out by ultrasound-assisted extraction (UAE) on fresh and freeze-dried samples. UAE extract, obtained by double extraction of freeze-dried apple pomace, was subjected to chromatographic and spectrophotometric characterization. It showed good levels of total phenol content, high antioxidant activity, and interesting antioxidant compounds (quercetin derivatives, chlorogenic acid, phloridzin). Subsequently, freeze-dried apple pomace, containing 40.19% of dietary fibre, was used as a fortifying agent for beef burgers (4% and 8%). The results concerning colour and sensory analysis of the fortified products were graded even better than the control (0%). The improved fibre and phenol content, together with the neutral flavour, represent the most interesting characteristics of fortified burgers. The results confirm that UAE was a successful technique for extracting phenol compounds and that the addition of apple pomace represents a valid approach to increase the health properties and palatability of beef burgers, including for consumers who do not like meat.

Meat alternatives: A proofed commodity?

The demand for meat alternatives has been growing in the recent years and it is expected to keep expanding. Motives driving this growth are diverse and are mostly related to the health and ethical concerns over animal welfare and the possible impact of meat production on the environment. Meat alternatives are not anymore a niche market (i.e., vegetarians and vegans) but going mainstream (also consumed by meat eaters and flexitarians). This can be attributed to advances in formulations and ingredients and innovative technologies resulting in improved quality of products. This chapter summarizes the current knowledge about meat alternatives (from plant, fungi or/and algae). Plant-based alternatives are already a proofed commodity with a wide range of products available in the market. The search for more sustainable sources had put the spotlight on other sources such as fungi and algae due to their limited need to land, energy and water for biomass production. Fungi-based alternatives are steps ahead of those algae-based owing to fungi neutral flavor, comparable nutritional profile to meat and no need to masking agents. Consumer acceptance is still a key challenge boosting research and development efforts to ensure a better quality, affordability, and sustainability.

Another look at the extinction of conditioned flavor preferences: Amount of training and tests for spontaneous recovery.

A conditioned flavor preference develops when hungry or thirsty rats experience a neutral flavor mixed in solution with a nutrient. In two sets of studies, we previously demonstrated that this learned preference is highly sensitive to flavor nonreinforcement (i.e., exposure to the flavor without the nutrient) either prior to (latent inhibition), during (partial reinforcement), or following (extinction) flavor-nutrient pairings. In each of these studies we employed a nutrient devaluation procedure to assess the integrity of specific flavor-nutrient associations following extinction, but more recently Gonzalez, Morillas, and Hall (Journal of Experimental Psychology: Animal Learning & Cognition, 42, 380-390, 2016) observed that sensitivity to extinction in thirsty rats in this preparation may depend upon use of a post-conditioning nutrient devaluation procedure. To assess the generality of our earlier results, but without including a post-conditioning nutrient devaluation phase, we assessed in three experiments the role of the number of flavor-nutrient pairings given prior to extinction and the possibility of spontaneous recovery following a 3-week delay. We observed that extinction consistently weakened the flavor preference in thirsty rats (in spite of the absence of a nutrient devaluation procedure) and also found no evidence for spontaneous recovery. These results establish that our prior findings that conditioned flavor preferences are weakened by extinction are quite robust in thirsty rats and that these extinction effects may be fairly permanent.

Development and characterization of green banana-based fondant icing

ABSTRACT The insertion of functional foods in the confectionery industry is a growing reality, aiming to meet a growing demand for products that are visually attractive and at the same time healthy. The present study aimed to develop and characterize the physical, physicochemical, microbiological, and sensory properties of fondant icings based on green banana biomass and flour. Two formulations were developed (NFBI - Neutral Flavor Biomass-based Icing, and CFBI - Chocolate Flavor Biomass-based Icing), which were compared with the commercial fondant icings (NFCI - Neutral Flavor Commercial Icing, and CFCI - Chocolate Flavor Commercial Icing). The fondant icings were evaluated for centesimal composition, caloric value, physical, physicochemical (resistant starch, titratable acidity, water activity, texture, and color), and microbiological characteristics, as well as sensory acceptance. The icings based on green banana biomass and flour showed higher levels of ash, fiber, resistant starch, and protein, as well as lower total caloric value, and thus, were healthier. These icings were also softer and had more intense color compared to commercial ones, as well as good sensory acceptance, especially the one with chocolate flavor, which had greater than 72% approval. Microbiological analyses indicated that the icings could be stored under refrigeration (&lt;4 ºC) for 30 days. Given the nutritional quality and health benefits, the icings prepared with green banana biomass and flour proved to be promising and could serve a niche market represented by people who seek a healthier diet or need to control their sugar consumption, such as diabetics.

Food technology to process plant-based food (soy protein isolate formula)

Soy protein isolate (SPI) is obtained by extracting the soluble protein and removing non-protein material such as fat and carbohydrates. Because of this process, it has a neutral flavor and cause less flatulence than soy flours. Furthermore, SPI has higher Protein Digestibility Corrected Amino Acid Score (PDCAAS) compared to soymilk, which is 100% and 92.6% respectively.

Genome-wide association studies for waxy starch in cassava

Cassava (Manihot esculenta Crantz) is an important crop for starch production, and recently much effort has been directed towards improving its starch properties. Waxy cassava starch has some advantages over starch from other sources due to its neutral flavor and pasting properties. The genetic inheritance of the waxy starch phenotype is considered to be monogenic and recessive; however, it is possible that other genomic regions contribute to the waxy phenotype. The aim of this study was to evaluate the power of genome-wide association studies (GWAS) to detect variants related to waxy starch and to identify alternative genes or genomic regions. For this purpose, a set of 382 samples (waxy and non-waxy) was analyzed using a panel of 20,956 single nucleotide polymorphisms (SNPs). All genotypes were evaluated in relation to the presence of waxy starch, determined using the 2% iodine test. The GWAS was performed using the retrospective CAse–control Retrospective Association Testing (CARAT) model. Kinship and population structure were also investigated and added to the model. Ten SNPs were found to be significant and located on chromosome 2 and co-located in genomic regions. The significant SNPs are in a region near the Granule-bound starch synthase I (GBSSI) and Beta-amylase genes. Additive and epistatic effects were also found among the significant SNPs, and these need to be better investigated in segregant populations of waxy sources. The regions and genes identified in this work may drive further studies and reveal biological processes related to the waxy phenotype.

Comparison of two rapid descriptive sensory techniques for profiling and screening of drivers of liking of sorghum breads

Rapid descriptive methods have emerged as a relatively simple alternative for screening the sensory attributes of products that drive their liking, and may contribute to identify sorghum genotypes with potential for development of gluten-free breads with higher consumer acceptance. Two rapid techniques, Check-All-That-Apply (CATA) and Optimized Descriptive Profile (ODP), were herein compared on their ability to describe, discriminate and identify the drivers of liking of sorghum breads. Gluten-free bread formulations were developed using flours from selected sorghum genotypes (CMSS005, BR 501, BRS 332, BRS 330, BRS 305 and 1167048), besides commercial sorghum and rice flours. A semi-trained panel (n = 18) evaluated the samples using the ODP method, whereas consumers (n = 124) completed the CATA questionnaire and rated the liking in a 9-point hedonic scale. A total of 24 and 11 sensory descriptors were perceived by assessors as different among samples for CATA and ODP, respectively, with color and appearance-related attributes critical to discriminate samples in CATA, whereas flavor and texture descriptors had also prominent contribution in ODP. A similar pattern of sample distribution was noticed for both methods, which were shown to be highly and positively correlated (RV = 0.92, p < 0.002). Genotypes influenced the consumer perception of sorghum breads, being the BRS 332 and the CMSS005 breads among the most and the least accepted samples for either consumer segment, respectively. While 10 drivers of liking were identified by CATA, including ‘appearance of whole flour breads’, ‘uniform alveoli’, ‘neutral flavor’ and ‘soft aroma’, in ODP ‘crumb color’, ‘crust color’, ‘spots’ and ‘traditional bread aroma’ drove bread acceptance. In summary, both methods were successfully applied and provided similar pattern of sample discrimination, whereas the attributes used for sample characterization, as well as those identified as drivers of liking were generally different. The ODP offers a simpler option for a quantitative perspective, while CATA remains as an easy method considering qualitative aspects, being clearly faster than ODP.

Discovery and Validation of Banana Intake Biomarkers Using Untargeted Metabolomics in Human Intervention and Cross-sectional Studies

BackgroundBanana is one of the most widely consumed fruits in the world. However, information regarding its health effects is scarce. Biomarkers of banana intake would allow a more accurate assessment of its consumption in nutrition studies. ObjectivesUsing an untargeted metabolomics approach, we aimed to identify the banana-derived metabolites present in urine after consumption, including new candidate biomarkers of banana intake. MethodsA randomized controlled study with a crossover design was performed on 12 healthy subjects (6 men, 6 women, mean ± SD age: 30.0 ± 4.9 y; mean ± SD BMI: 22.5 ± 2.3 kg/m2). Subjects underwent 2 dietary interventions: 1) 250 mL control drink (Fresubin 2 kcal fiber, neutral flavor; Fresenius Kabi), and 2) 240 g banana + 150 mL control drink. Twenty-four-hour urine samples were collected and analyzed with ultra-performance liquid chromatography coupled to a quadrupole time-of-flight MS and 2-dimensional GC-MS. The discovered biomarkers were confirmed in a cross-sectional study [KarMeN (Karlsruhe Metabolomics and Nutrition study)] in which 78 subjects (mean BMI: 22.8; mean age: 47 y) were selected reflecting high intake (126–378 g/d), low intake (47.3–94.5 g/d), and nonconsumption of banana. The confirmed biomarkers were examined singly or in combinations, for established criteria of validation for biomarkers of food intake. ResultsWe identified 33 potentially bioactive banana metabolites, of which 5 metabolites, methoxyeugenol glucuronide (MEUG-GLUC), dopamine sulfate (DOP-S), salsolinol sulfate, xanthurenic acid, and 6-hydroxy-1-methyl-1,2,3,4-tetrahydro-β-carboline sulfate, were confirmed as candidate intake biomarkers. We demonstrated that the combination of MEUG-GLUC and DOP-S performed best in predicting banana intake in high (AUCtest = 0.92) and low (AUCtest = 0.87) consumers. The new biomarkers met key criteria establishing their current applicability in nutrition and health research for assessing the occurrence of banana intake. ConclusionsOur metabolomics study in healthy men and women revealed new putative bioactive metabolites of banana and a combined biomarker of intake. These findings will help to better decipher the health effects of banana in future focused studies. This study was registered at clinicaltrials.gov as NCT03581955 and with the Ethical Committee for the Protection of Human Subjects Sud-Est 6 as CPP AU 1251, IDRCB 2016-A0013–48; the KarMeN study was registered with the German Clinical Trials Register (DRKS00004890). Details about the study can be obtained from https://www.drks.de.

Enhancement of table grape flavor by postharvest application of monoterpenes in modified atmosphere

Consumers expect ready-to-eat grapes to have excellent quality and flavor. In practice, most table grape cultivars have a neutral flavor relying mainly on the combination of sugar and acidity due to limited levels of volatiles that impart the unique aromas. This study investigated the possibility of improving grape flavor by incubating the berries in monoterpene-enriched modified atmosphere. The berries were sanitized by dipping in ethanol and packaged in trays sealed with plastic films of different perforation levels. The optimal conditions selected for further study were one micro-perforation per package containing 250 g berries and storage at 5 ℃ for 2 weeks. To test the possibility of improving grape flavor during storage, berries of the cultivars Flame Seedless, Adominique, 4111 and Crimson Seedless were stored in the presence of the monoterpenes linalool or geraniol. After two weeks of storage in the presence of linalool, it accumulated in the berries to levels of 551, 704 and 3273 μg kg−1 in Adominique, 4111 and Crimson Seedless, respectively. Application of linalool or geraniol resulted in appearance of many other monoterpenes, probably by the action of endogenous enzymes. Organoleptic preference assays indicated that berries of Adominique and 4111 stored in the presence of linalool were favored over the control berries. Overall, the results demonstrate the feasibility of using monoterpenes to enhance berry flavor during storage.

Licking microstructure and hedonic changes after flavour preference learning in rats.

Pairing a neutral flavour conditioned stimulus (CS) with a nutrient reward will create a learned preference for that CS. Prior studies suggest that this is accompanied by an increase in the hedonic value of the CS, although the reliability of this effect is yet to be fully established. Here, flavour CS+s were mixed with either 16% sucrose or maltodextrin (with control CS-s mixed with 2% solutions of the same carbohydrate). While a reliable preference for the CS+ was seen in every case, and there was a learned increase in lick cluster size when all conditions were considered together, this difference was significant in only one experimental condition considered alone. A meta-analysis of these results and similar published licking microstructure analysis studies found that the Cohen's dav effect size for changes in licking microstructure after flavour preference learning was 0.16. This is far smaller than the effect sizes reported when assessing learned hedonic changes in flavour preference based on other test or training methods. Although this confirms that flavour preference learning produces hedonic changes in the cue flavours, the analysis of licking microstructure with training based on voluntary consumption of CS and unconditioned stimulus (US) compounds may be an insensitive means of assessing such effects.

Impact of lactic acid bacteria starter cultures and hydrolytic enzymes on the characteristics of wholegrain crackers

This work studied the impact of bioprocessing with lactic acid bacteria starter cultures (dextran producing Weissella confusa and Lactobacillus plantarum) and proteolytic and xylanolytic enzymes on structural, chemical and sensory characteristics of wholegrain wheat crackers. Bioprocessing of flour increased free amino acids content (FAA) and water extractable arabinoxylans (WEAX). W. confusa fermentation increased FAA the most (0.46–0.48 g/100 g) compared to the control (0.22 g/100 g). Treatment with xylanase and fungal protease showed highest WEAX (2.29 g/100 g vs. 0.90 g/100 g). This cracker was also the thickest. Fermentation with W. confusa without dextran production decreased thickness, while dextran containing W. confusa samples were similar to the control. Cracker thickness and flour RVA-viscosities showed negative correlation. Non-dextran W. confusa increased final viscosity (1807 cP) and setback viscosity (1200 cP) compared to control flour (1318 cP and 885.5 cP). Both enzyme-types reduced viscosities: e.g. lowest final viscosity was 729.5 cP after protease treatment. Microscopy indicated enhanced gluten network especially after xylanase treatment. Enzyme-treated crackers had neutral flavor and soft structure, as well as increased tendency to break down in the mouth. Fermented crackers were hard and had pungent flavour. Acidification appeared to negate the possible positive impact of dextran on cracker quality.