Performance of an Expert Sensory Panel and Instrumental Measures for Assessing Eating Fruit Quality Attributes in a Pear Breeding Programme

Breeding programmes count on stable trained panels that support breeding evaluation selections. This work aimed to evaluate the performance of a small expert panel in the join IRTA-PFR breeding programme to validate its use in the sensory assessments of fruit pear genotypes during the selection process. A breeding F1 population of 80 pear seedlings from this programme was used. Descriptors and standard references used for sensory evaluations of pear attributes were previously defined by the four members of the expert panel. A General Procrustes Analysis (GPA) was applied to analyse the relations between instrumental and sensory traits. The results showed a good relationship between sensory attributes such as firmness and crispness with penetrometer measures. A high correlation was also found between sensory sourness and titratable acidity (TA). Panel performance was evaluated in terms of reproducibility, homogeneity, and panel consonance. The results indicated that the experts were very consistent and had a good performance. The work demonstrates, for the first time, that a small expert trained panel could be efficiently used in pear breeding programmes and allows for the selection process in a more economical and available way in contrast to the larger sensory panels conventionally used.info:eu-repo/semantics/publishedVersio

Ripening behaviour and consumer acceptance of ‘Conference’ pears during shelf life after long term DCA-storage

With the increasing demand for ready to eat fruit, understanding how pear quality evolves during shelf life (SL) is of paramount importance for retailers. Accordingly, the relationships between physicochemical quality parameters, the emission of volatile compounds and consumer satisfaction were investigated in ‘Conference’ pears from different orchards and stored at 20 °C following 8 months of cold storage (-0.5 °C) under dynamic controlled atmosphere (DCA). Our results showed that DCA storage strongly inhibits firmness loss ( 0.96). Prolonged DCA storage of Conference did not completely impede ripening as indicated by the reducing trend of IAD and the ethylene postclimacteric behavior of the fruit during SL. In parallel to the decrease of firmness during SL, there was a consistent increase in most ester-type volatiles and especially in hexyl acetate and butyl acetate. Generally, the highest consumer satisfaction after DCA cold storage of ‘Conference’ pears was reached after 3 d at 20 °C. In this sense, the most appreciated pears by consumer were those showing high flavour in combination with firmness values in the range of 10–30 N. The Partial Least Square (PLS) model showed that total soluble solids (TSS), the ratio TSS/TTA (total titratable acidity), consumer flavour perception and some particular volatile compounds (i.e. methyl, ethyl and hexyl acetates as well as ethyl trans,cis-2,4-decadienoate) were positively correlated to consumer’s overall liking while firmness, TTA and index of absorbance difference (IAD) had a negative correlation and higher prediction capability.info:eu-repo/semantics/acceptedVersio

A comprehensive study on the main physiological and biochemical changes occurring during growth and on-tree ripening of two apple varieties with different postharvest behaviour

Apple quality and the storage potential likely depend on a range of physiological and biochemical events occurring throughout fruit development and ripening. In this study, we investigated the major physiological (ethylene production and respiration) and biochemical changes (related to sugar and malic acid content as well as antioxidant metabolism) occurring during growth and on-tree ripening of two apple varieties (‘Granny Smith’ (GS) and ‘Early Red One’ (ERO)) with known differences in their postharvest behaviour, mainly firmness loss and susceptibility to superficial scald. Our results demonstrate that the higher storability and the limited loss of firmness of ‘GS’ fruit was associated to a higher acid content, mainly malic acid, that seemed to be regulated already at fruit set (20 DAFB). The reduced loss of firmness during storage in ‘GS’ was also associated to the fruit inability to produce ethylene upon harvest resulting from very low 1-aminocyclopropane-1-carboxylic acid oxidase (ACO) activity. Sugar accumulation, on the other hand, was similar among both varieties as was also observed for the rate of fruit growth or the fruit respiration pattern. In addition, the higher susceptibility of ‘GS’ if compared to ‘ERO’ to superficial scald was not associated to peroxidative damage (malondialdehyde accumulation) nor to higher levels of the sesquiterpene α-farnesene but rather mediated by a fruit antioxidant imbalance resulting from higher H2O2 levels and lower antioxidant (peroxidase) enzymatic capacity. The interplay between ethylene, respiration and antioxidants or sugars and organic acids during apple growth and development is further discussed.info:eu-repo/semantics/acceptedVersio

Spatial distribution of flavor components and antioxidants in the flesh of ‘Conference’ pears and its relationship with postharvest pathogens susceptibility

The spatial distribution of dry matter, ethylene production, respiration rate, organic acids, sugars, antioxidants, volatiles and fungal (Penicillium expansum and Rhizopus stolonifer) growth was evaluated analyzing four different slices of ‘Conference’ pear flesh taken along an equatorial radius. A common spatial distribution trend was found for ethylene emission, CO2 production, antioxidant capacity and total phenolic compounds with a minimum in the slice under the skin and a maximum in the slice near the core. Fructose, which was the dominant sugar followed by sucrose and glucose, showed a quasi-linear decreasing profile from the outer slice towards the core. Malic and ascorbic acid had the highest content in the outer slice while citric remained practically constant over the different slices. Twenty-nine volatile organic compounds (VOCs) were identified using solid-phase microextraction (SPME), yet only six of them showed significant differences between flesh slices. The content in VOCs was further related to the tissue susceptibility to the above-mentioned postharvest pathogens using a multivariate approach. Fruit flesh from inner sections was more prone to P. expansum whereas flesh from the slice under the skin presented the highest incidence of R. stolonifer. A Partial Least Square (PLS) model showed that P. expansum growth was negatively correlated with malic acid, dry matter content, 2-ethyl-hexanal and butyl hexanoate concentrations and R. stolonifer was negatively correlated to sucrose and some volatiles such as hexanal and 1-butanol. Based on the results from the PLS, selected volatiles naturally present in the pear flesh were tested in vitro, at different concentrations, in order to investigate their effectiveness to control blue mold caused by P. expansum and soft rot caused by R. stolonifer. A completely control of P. expansum was found with 2-ethyl-hexanal application and hexanal while 1-butanol showed a total fungicide effect against R. stolonifer. This study is a step towards a better understanding of how biochemical compounds are spatially distributed among different slices of ‘Conference’ pears as well as in the development of natural compounds to fight major postharvest pathogens in pear fruit.info:eu-repo/semantics/acceptedVersio

Investigation of the transcriptomic and metabolic changes associated with superficial scald physiology impaired by lovastatin and 1-methylcyclopropene in pear fruit (cv. “Blanquilla”)

To elucidate the physiology underlying the development of superficial scald in pears, susceptible “Blanquilla” fruit was treated with different compounds that either promoted (ethylene) or repressed (1-methylcyclopropene and lovastatin) the incidence of this disorder after 4 months of cold storage. Our data show that scald was negligible for the fruit treated with 1-methylcyclopropene or lovastatin, but highly manifested in untreated (78% incidence) or ethylene-treated fruit (97% incidence). The comparison between the fruit metabolomic profile and transcriptome evidenced a distinct reprogramming associated with each treatment. In all treated samples, cold storage led to an activation of a cold-acclimation-resistance mechanism, including the biosynthesis of very-long-chain fatty acids, which was especially evident in 1-methylcyclopropane-treated fruit. Among the treatments applied, only 1-methylcyclopropene inhibited ethylene production, hence supporting the involvement of this hormone in the development of scald. However, a common repression effect on the PPO gene combined with higher sorbitol content was found for both lovastatin and 1-methylcyclopropene-treated samples, suggesting also a non-ethylene-mediated process preventing the development of this disorder. The results presented in this work represent a step forward to better understand the physiological mechanisms governing the etiology of superficial scald in pears.info:eu-repo/semantics/publishedVersio

Genetic analysis of the slow melting flesh character in peach

The slow-melting flesh (SMF) trait in peach [Prunus persica (L.) Batsch] defines a slower process of postharvest fruit-softening than the prevalent melting flesh (MF) types. This gives a longer shelf life and a delayed harvest-time resulting in better fruit quality. Unlike other known fruit texture traits, SMF is difficult to measure and has a complex inheritance. We examined this character over 2 years in the offspring of two crosses, both with "Big Top," an SMF nectarine, as the female parent, and with a melting flesh (MF) nectarine as the male parent ("Armking" and "Nectaross"). Following harvest, a texturometer was used to provide a textural profile analysis, and fruit firmness evolution was measured with a penetrometer over a period of 5 days' storage at 20 °C. Linkage maps were constructed with a high-density SNP chip, and a phenotype-genotype analysis allowed the detection of three independent genomic regions where most QTLs (quantitative trait loci) were located. Two of these, on linkage groups 4 and 5, explained the variability for two characters-maturity date and firmness loss-that is, the QTL on linkage group 4 found in the MF parents and that on linkage group 5 in Big Top. A third region on linkage group 6, which identified a QTL for maturity date only in Armking, has no apparent association to the softening process. The relationship between maturity date and fruit-firmness loss and a hypothesis on the inheritance of the SMF character are discussed

Current situation, trends and challenges for efficient and sustainable peach production

In Spain, the total surface occupied by deciduous fruit species in 2019 was 190,414 ha. Peach is the second most important Prunus species with 77,464 ha and a production of 1,480,000 t per year. Labour is the main production cost, amounting to 45% of the total cost in 2020 and primarily involving pruning, thinning and harvesting. The common trend regarding agronomical orchard models, in deciduous fruit species, is planting intensification, combining mid to low vigour rootstocks and training systems based on small, bi-dimensional canopies. Sizecontrolling rootstocks such as Rootpac-40, Isthara or Adesoto-101, Among others, resulted in better yield efficiency and improved fruit quality compared with GF-677. In 7-year-old trees of ‘Luciana’ nectarine cultivar, the use of size-controlling rootstock Rootpac-40 and an intensive orchard trained in central leader allowed both earlier and higher yields, resulting in a difference of 102 tha− 1 compared with the standard Spanish gobolet system on GF-677. With ‘Noracila’ and the same combinations, the difference was 109 tha− 1. The central leader/ single row and central leader/double row training systems, despite requiring a greater orchard establishment cost, gave earlier and higher yields in ‘Ambra’ and ‘Luciana’ cultivars grafted on G-677, around 48% for double row and 30% for single row, compared to the Spanish gobelet system. Planar canopies allowed an efficient use of mechanical and manual pruning and flower thinning, which improved harvest efficiency (kg.h− 1) by 28%. As a result, a production cost reduction of around 15% was recorded in comparison to the Spanish gobelet system. Greater efficiency in total labour per season enabled a reduction of 39%, from 651 h.ha− 1 for the Spanish gobelet system to 398 h.ha− 1 for the central leader system. Additionally, an increase in fruit quality, particularly fruit size and SSC content, due to a more uniform light distribution was observed. In these planar intensive systems, including palmette, a reduction in light interception of 17% was recorded when compared to the open vase system. Yields obtained were more related to planting density and canopy architecture than the average of intercepted light. Currently, the central leader and bi-axis are the most important systems used in intensive orchards in Spain, with planting densities from 1,900 to 3,100 trees.ha− 1. All these results support the sustainable intensification concept and make peach tree production more economically sustainable for growers.info:eu-repo/semantics/acceptedVersio

Defining key parameters and predictive markers of ‘Early Bigi’ cherry consumer satisfaction by means of differential storage scenarios

To induce differences in sensorial characteristics, ‘Early Bigi’ cherries were exposed to various storage scenarios, including modified atmosphere packaging, 1-methylcyclopropene and methyl jasmonate treatments. Three classes of consumer acceptance (high, medium, and low) were defined and related to changes in standard quality, flavour perception and volatile organic compounds (VOCs) emissions. Consumer satisfaction in ‘Early Bigi’ cherries strongly depended on the acidity levels of the fruit and how the storage scenario modulated this parameter. Multivariate data analysis also revealed a clear relationship between acidity, VOCs emissions and flavour perception that determined fruit acceptance. In this cultivar, flavour perception and consumer satisfaction were also linked to specific volatile compounds. At harvest and during the first 15 d of cold storage, consumer satisfaction was found to mainly depend on high levels of ethyl butanoate, (Z)-3-hexen-1-ol and benzaldehyde and on the other side on low levels of ethyl acetate and ethanol, which were probably perceived as off-flavours or unpleasant compounds. Consumer satisfaction was also related to low levels of 2-methylbutyl butanoate, (Z)-2-hexenyl acetate, linalool and 3-methyl-2-butanol. It is, therefore, possible to envisage the use of these specific volatile compounds as markers for consumer satisfaction in ‘Early Bigi’ cherries and perhaps also in other cherry cultivarsinfo:eu-repo/semantics/acceptedVersio

Cultivar differences in the hormonal crosstalk regulating apple fruit development and ripening: Relationship with flavour components and postharvest susceptibility to Penicillium expansum

The hormonal interplay during the on-tree development and ripening of three apple cultivars with known differences in their postharvest ripening patterns was studied, at the biochemical and targeted gene expression level, along with characterizing the changes in main sugars, acids, phenylpropanoids and volatile organic compounds (VOCs). Our findings suggest that in ‘Royal Gala’ and ‘Opal®’ apples, a peak in indole 3-acetic acid (IAA) seems necessary to activate ethylene metabolism, being its intensity proportional to the ethylene production. The interplay between IAA and ethylene appears to be mediated by MdARF5, responsible for activating the expression of MdACS3 and triggering ethylene metabolism. On the other hand, the lack of ethylene production observed in ‘Granny Smith’ apples was likely related to the absence of an IAA peak and possibly caused by the over activation of IAA conjugation mechanisms leading to a greater accumulation of IAA inactive conjugates such as indole-3-acetyl-aspartate (IAAsp). Abscisic acid (ABA) accumulation was only observed in cultivars with the ability to accumulate sucrose and produce ethylene, suggesting a possible crosstalk among those hormones and sucrose in orchestrating apple on-tree ripening. While differences in hormone levels among cultivars led to noticeable differences in some specific VOCs, no evident associations were found between hormone changes and the accumulation or degradation of monosaccharides, organic acids or phenolic compounds during fruit development and ripening. Likewise, no clear relationship was found between the fruit susceptibility to blue mould and hormonal levels yet certain specific biochemical compounds (i.e., procyanidins and sucrose) could be acting as a source of resistance or susceptibility, respectively, to blue mould development. Overall, understanding the cultivar specific hormonal regulation of apple on-tree ripening provides valuable insights to optimize fruit quality at the time of harvest as well as to develop strategies for improved postharvest management.This work has been financially supported by the Spanish Agencia Estatal de Investigación (AEI) and European Regional Development Fund (ERDF) through the national project PID2020-117607RR-I00 (ENVIRONAPPLE)

The Role of sensory experience on Spanish consumer’s willingness to pay for sustainable produced food

For a variety of reasons, Spanish growth in demand for organic and integrated products has not kept up with supply. This work focused on the effect of information and sensory issues on purchase behaviour in relation to sustainable agricultural production. Using experimental auctions and results from (trained and untrained) sensory Panels, we studied the preferences for attributes related to food sustainability. Spanish consumers have a positive attitude towards sustainable food due to environmental concerns, health concerns, and trust in certification and market agents. However, the premium they are willing to pay for these products is lower than the current market price. Furthermore, “search” and sensory “experience” influence consumers’ purchase behavior