The genetic and functional analysis of flavor in commercial tomato: the FLORAL4 gene underlies a QTL for floral aroma volatiles in tomato fruit.

Tomato (Solanum lycopersicum L.) has become a popular model for genetic studies of fruit flavor in the last two decades. In this article we present a study of tomato fruit flavor, including an analysis of the genetic, metabolic and sensorial variation of a collection of contemporary commercial glasshouse tomato cultivars, followed by a validation of the associations found by quantitative trait locus (QTL) analysis of representative biparental segregating populations. This led to the identification of the major sensorial and chemical components determining fruit flavor variation and detection of the underlying QTLs. The high representation of QTL haplotypes in the breeders' germplasm suggests that there is great potential for applying these QTLs in current breeding programs aimed at improving tomato flavor. A QTL on chromosome 4 was found to affect the levels of the phenylalanine-derived volatiles (PHEVs) 2-phenylethanol, phenylacetaldehyde and 1-nitro-2-phenylethane. Fruits of near-isogenic lines contrasting for this locus and in the composition of PHEVs significantly differed in the perception of fruity and rose-hip-like aroma. The PHEV locus was fine mapped, which allowed for the identification of FLORAL4 as a candidate gene for PHEV regulation. Using a gene-editing-based (CRISPR-CAS9) reverse-genetics approach, FLORAL4 was demonstrated to be the key factor in this QTL affecting PHEV accumulation in tomato fruit.

A validated survey to measure household food waste.

To assess household food waste in large-scale studies with the aim to understand differences in food waste levels between households, surveys are often employed. Yet, survey measures rely on people's awareness of their own food waste levels, draw upon their memory of instances of food waste, and can be subject to social desirability. Therefore, existing survey measures may not be optimal in measuring household food waste. The Household Food Waste Questionnaire has been developed to ameliorate these issues. It uses a pre-announcement to increase awareness of food waste, focuses on a short and specific time period (i.e. the past week), and specifies detailed product categories, whereas previous surveys mostly used general questions without reference to time period or product category. The amount of household food waste estimated using the Household Food Waste Questionnaire is likely to considerably underestimate the actual amount, so the method should not be used to obtain accurate waste amounts, but rather to distinguish differences between households and/or across time. Advantages compared to existing survey methods are that it: •Distinguishes better between households with low versus high levels of food waste•Correlates more highly with other measurements of household food waste (diary, kitchen caddy, photograph coding).

Comparing wasted apples and oranges: An assessment of methods to measure household food waste.

Food waste has become a global concern in recent years, especially the household food waste that is generated in the developed world. Multiple methods to measure household food waste have been proposed, but little is known about their validity. Five methods are selected and investigated empirically: survey questions about general food waste over a non-specified period of time, diaries, photo coding, kitchen caddies, and pre-announced survey questions regarding a specific time period. In an experiment, respondents were asked to assess their food waste using some or all of these methods depending on condition. Overall, the general survey questions appear to be less valid, as these lead to large underestimation of the level of food waste, low variance in reported food waste across households compared to the other methods, and low correlations with other measures. The other four methods are relatively highly correlated. A survey about food waste in the past week appears to be a useful method for large-scale measurements to differentiate households according to the amount of food waste each produces, although it should be noted that this method underestimates the amount of food waste. Kitchen caddies and photo coding seem to be valid methods and, for small samples, provide alternatives to food diaries, which have been more commonly used.

Fresh, frozen, or ambient food equivalents and their impact on food waste generation in Dutch households.

In Europe, it is estimated that more than 50% of total food waste - of which most is avoidable - is generated at household level. Little attention has been paid to the impact on food waste generation of consuming food products that differ in their method of food preservation. This exploratory study surveyed product-specific possible impacts of different methods of food preservation on food waste generation in Dutch households. To this end, a food waste index was calculated to enable relative comparisons of the amounts of food waste from the same type of foods with different preservation methods on an annual basis. The results show that, for the majority of frozen food equivalents, smaller amounts were wasted compared to their fresh or ambient equivalents. The waste index (WI) proposed in the current paper confirms the hypothesis that it may be possible to reduce the amount of food waste at household level by encouraging Dutch consumers to use (certain) foods more frequently in a frozen form (instead of fresh or ambient). However, before this approach can be scaled to population level, a more detailed understanding of the underlying behavioural causes with regard to food provisioning and handling and possible interactions is required.

Sensory quality of drinking water produced by reverse osmosis membrane filtration followed by remineralisation.

Membrane filtration of ground, surface, or sea water by reverse osmosis results in permeate, which is almost free from minerals. Minerals may be added afterwards, not only to comply with (legal) standards and to enhance chemical stability, but also to improve the taste of drinking water made from permeate. Both the nature and the concentrations of added minerals affect the taste of the water and in turn its acceptance by consumers. The aim of this study was to examine differences in taste between various remineralised drinking waters. Samples selected varied in mineral composition, i.e. tap water, permeate, and permeate with added minerals (40 or 120 mg Ca/L, added as CaCO3, and 4 or 24 mg Mg/L added as MgCl2), as well as commercially available bottled drinking waters, to span a relevant product space in which the remineralised samples could be compared. All samples were analysed with respect to their physical-chemical properties. Sensory profiling was done by descriptive analysis using a trained panel. Significant attributes included taste intensity, the tastes bitter, sweet, salt, metal, fresh and dry mouthfeel, bitter and metal aftertaste, and rough afterfeel. Total dissolved solids (TDS) was a major determinant of the taste perception of water. In general, lowering mineral content in drinking water in the range examined (from <5 to 440 mg/L) shifted the sensory perception of water from fresh towards bitter, dry, and rough sensations. In addition, perceived freshness of the waters correlated positively with calcium concentration. The greatest fresh taste was found for water with a TDS between 190 and 350 mg/L. Remineralisation of water after reverse osmosis can improve drinking quality significantly.

Non-smoky glycosyltransferase1 prevents the release of smoky aroma from tomato fruit.

Phenylpropanoid volatiles are responsible for the key tomato fruit (Solanum lycopersicum) aroma attribute termed "smoky." Release of these volatiles from their glycosylated precursors, rather than their biosynthesis, is the major determinant of smoky aroma in cultivated tomato. using a combinatorial omics approach, we identified the non-smoky glycosyltransferase1 (NSGT1) gene. Expression of NSGT1 is induced during fruit ripening, and the encoded enzyme converts the cleavable diglycosides of the smoky-related phenylpropanoid volatiles into noncleavable triglycosides, thereby preventing their deglycosylation and release from tomato fruit upon tissue disruption. In an nsgt1/nsgt1 background, further glycosylation of phenylpropanoid volatile diglycosides does not occur, thereby enabling their cleavage and the release of corresponding volatiles. Using reverse genetics approaches, the NSGT1-mediated glycosylation was shown to be the molecular mechanism underlying the major quantitative trait locus for smoky aroma. Sensory trials with transgenic fruits, in which the inactive nsgt1 was complemented with the functional NSGT1, showed a significant and perceivable reduction in smoky aroma. NSGT1 may be used in a precision breeding strategy toward development of tomato fruits with distinct flavor phenotypes.