Incidental learning and memory for food varied in sweet taste in children

This experiment investigated incidental learning and memory in children (age 7-10 years) for three different foods (fruit juice, fruit purée and biscuit), varied in sweetness. Children (N = 286) were exposed to three target foods and 24 h later their incidental learning was tested for one of the foods by asking them to recognize the target among distractors varying in sweetness. Children were also asked to rate their liking for the products.Overall, the children showed incidental learning for the food eaten the previous day, but recognition was not equal for all stimuli: a memory effect was found for fruit purée but not for biscuit and fruit juice. Memory was based on the correct rejection of the distractors rather than on target recognition. Hedonic scores were high, but lowest for fruit purée. Memory was not related to liking, but it is likely that other factors like novelty and familiarity may have been influential.     

Modulation of perceived taste by olfaction in familiar and unfamiliar beverages

The integration of olfactory and taste perception and the role of congruency and familiarity on perception have already been demonstrated in model solutions. The aim of the present study was to investigate the role of these factors in real food products. Therefore, we have investigated the impact of olfactory perception on perceived bitterness in a familiar (bitter cocoa beverage) and an unfamiliar (bitter milk) beverage. Sensory profilings with and without noseclip were conducted according to simultaneous product presentation. In a first experiment, an instant cocoa powder mixed with water was used to prepare a common base. Two types of flavourings were added: cocoa and vanilla, at three different levels (none, medium and high). Samples were compared within a flavouring type. In a second experiment a vanilla flavour was added at three levels to a milk base containing caffeine. The panellists scored bitterness, sourness, sweetness and body with noseclip. Without noseclip, overall aroma above the cup and in mouth were assessed in addition to the previous set of attributes. With noseclip, results showed that neither the cocoa nor the vanilla flavourings provided any additional taste to the beverages. Without noseclip, olfactory/taste interaction in the cocoa beverage led to an enhancement of bitterness induced by the cocoa flavouring and an increase in sweetness from the vanilla flavouring. On the contrary, in the caffeinated milk, the addition of vanilla flavouring did not significantly increase sweetness, but unexpectedly enhanced bitterness. This study is further evidence of the influence of olfaction on taste perception in complex matrices. In addition, our results suggest that taste–olfaction integration is product dependent and related to food experience, even when working with trained subjects. Furthermore, the unpleasantness due to the neophobia related to the consumption of a new product and to bitterness may enhance bitterness when the unfamiliarity of the product is increased by addition of vanilla flavouring to a bitter milk beverage.     

Scapania nemorea liverwort extracts: Investigation on volatile compounds, in vitro antimicrobial activity and control of Saccharomyces cerevisiae in fruit juice

This study was focused on chemical characterisation of liverwort Scapania nemorea extracts and their antimicrobial activity against pathogenic and food-spoiling yeasts and bacteria. The chemical composition of three different extracts of the liverwort S. nemorea was determined by solid phase microextraction gas chromatography-mass spectrometry (SPME GC–MS). The dominant compounds in extracts were sesquiterpenes β-bazzanene (11%, 17.9% and 14.6%), isobazzanene (10.2%, 15.8% and 11.7%) and aromadendrene (8.8%, 12.9% and 10.6%) in the methanol, ethanol and ethyl acetate extracts, respectively. Antimicrobial potential of S. nemorea extracts against food spoiling yeasts and bacteria was determined in vitro by microdilution method. The Minimum Inhibitory Concentration (MIC) varied from 0.5 to 3 mg/mL for bacteria, and from 0.2 to 1 mg/mL for yeasts. Moreover, the combined effects of dry methanol extract of S. nemorea and heat processing on the survival and growth of a spoilage yeast in an apple/orange-based beverage, have been assessed through a Central Composite Design. Changes in color and flavor of the beverages were considered acceptable also after one week of storage at 25 °C. The results provide evidence of antimicrobial potential of S. nemorea extracts and suggest its potential as natural antimicrobial agent for food preservation.     

Textural properties of fruit affected by experimental conditions in TPA tests: an RSM approach

Texture profile analysis (TPA) is widely used to assess the textural properties of fruit. However, test parameters may potentially affect TPA results. This work studies the influence of the degree of deformation and crosshead speed on the mechanical parameters of apple measured by TPA. In this study, the degree of deformation ranged from 5% to 17.8% and the crosshead speed from 10 to 90 mm min^?1. Eight parameters were extracted from the analysis of force–displacement and force–time curves. For each parameter, the mean value and the coefficient of variation (CV) were examined. A central composite design that simultaneously takes into account both input variables, the degree of deformation and crosshead speed, was implemented. It appears that the linear and the quadratic effects of the degree of deformation make it the major variable. However, neglecting the effects (linear and quadratic) of the crosshead speed might be disastrous since they significantly affect parameters such as cohesiveness, gumminess and work 2. Moreover, the CV of hardness 1 depends mainly on the interaction between the degree of deformation and crosshead speed.     

Evaluation of Escherichia coli O157:H7 in apple juice with Cornus fruit (Cornus officinalis Sieb. et Zucc.) extract by conventional media and thin agar layer method

Escherichia coli O157:H7 survival in apple juice supplemented with Cornus fruit (Cornus officinalis Sieb. et Zucc.) extract was studied. Inoculated samples with or without Cornus fruit extract were kept at 21 and 7 degrees C. Microbial analysis was conducted on days 0, 1, 3, 5, and 7. MacConkey sorbitol agar (MSA), tryptic soy agar (TSA), and thin agar layer (TAL) medium were used to compare the recovery of bacteria stressed under combination treatment. Influence of temperature, storage time, and Cornus fruit on survival of cells was evaluated. The most dramatic reduction of E. coli O157:H7 was observed in apple juice with Cornus fruit extract at 21 degrees C. At 7 degrees C, E. coli O157:H7 was reduced by 2.3logcfu/ml in the apple juice with Cornus fruit extract compared to the control sample on day 7. TAL and TSA were more efficient than MSA. Cornus fruit extract can be used in combination with temperature and storage time controls to inactivate E. coli O157:H7 in apple juice. This study has shown that TAL is a viable method of recovering and differentiating injured microorganisms and apple juice supplemented with Cornus fruit has potential as a value-added beverage with antimicrobial effects and potential health benefits.     

Selected primary and secondary metabolites in fresh persimmon (Diospyros kaki Thunb.): A review of analytical methods and current knowledge of fruit composition and health benefits

Diospyros kaki Thunb. (Ebenaceae) is a widely cultivated tree species in some countries of Asia, while in other continents persimmons are mostly considered “exotic” fruits. Peculiar characteristics of this species are a complex sex expression, parthenocarpy and fruit astringency at harvest time, associated with a different composition in polymerized flavan-3-ols. Analytical methods for determining sugars, vitamin C, carotenoids and polyphenols in persimmons were critically reviewed in order to evaluate the overall significance of literature results; the nutritional and nutraceutical properties, together with the health benefits of both astringent and non astringent cultivars, were also overviewed. To these aims, the available literature from the last twenty years and the most important formerly published papers were investigated using SciFinder^®, Elsevier SciVerse, AGRIS, and PubMed search engines. Persimmons resulted rich in sugars (about 12.5 g/100 g FW), being fructose, glucose and sucrose the major components, and in total vitamin C, for which 100-150 g of fresh persimmon supplies the recommended daily amount. Astringent varieties supply higher amounts of sugars than nonastringent ones; conversely, higher concentrations of total vitamin C were found in nonastringent cultivars. The main carotenoid components are ??-cryptoxantin (193 ??g/100 g FW), ??,??-carotene (113 ??g/100 g FW) and ??,??-carotene (30 ??g/100 g FW). Persimmons are also a good source of polyphenolic compounds such as p-coumaric acid, catechin, epicatechin, epigallo catechin, and condensed proanthocyanidins. This chemical composition, together with in vivo and in vitro studies, suggests a relevant role of persimmon in the protection against free radicals and in the prevention of some human diseases.