The biocontrol potential of the Bacillus amyloliquefaciens strain BUZ-14 was tested against the main postharvest diseases of orange, apple, grape and stone fruit. After characterizing the temperature and pH growth curves of strain BUZ-14, its in vitro antifungal activity was determined against Botrytis cinerea, Monilinia fructicola, M. laxa, Penicillium digitatum, P. expansum and P. italicum. Subsequently, in vivo activity was tested against these pathogens by treating fruit with cells, endospores and cell-free supernatants. The in vitro results showed that BUZ-14 inhibited the growth of all the pathogens tested corresponding to the least susceptible species, P. italicum, and the most susceptible, M. laxa. In vivo tests corroborated these results as most of the treatments decreased the incidence of brown rot in stone fruit from 100% to 0%, establishing 107 CFU mL-1 as the minimum inhibitory concentration. For the Penicillium species a preventive treatment inhibited P. digitatum and P. italicum growth in oranges and reduced P. expansum incidence in apples from 100% to 20%. Finally, it has been demonstrated that BUZ-14 was able to survive and to control brown rot in peaches stored at cool temperatures, making it a very suitable biocontrol agent for application during the post-harvest storage and marketing of horticultural products.

32 Pags.- 4 Tabls.- 6 Fgs. The definitive version is available at: https://www.sciencedirect.com/science/journal/14668564Thinned fruits are agricultural by-products which nowadays have few economic or environmental benefits. However, previous studies have revealed that these immature fruits have a large amount of antioxidant compounds. The aim of this study was to evaluate whether pulsed electric fields (PEF) might be a suitable green technology for enhancing the extraction of phenols, flavonoids and antioxidant compounds from fresh thinned peaches, thus reducing the use of methanol. Moreover, response surface methodology has been used to determine the optimal PEF treatment conditions, observing that the solvent is the main factor. The highest amounts of bioactive compounds were extracted using 80% methanol and no PEF. Methanol combined with PEF produced a negative effect on the extraction yield. However, the use of water as a solvent increased the amount of total bioactive compounds and individual phenols (chlorogenic acid, coumaric acid and neochlorogenic acid). Thus, PEF-assisted extraction of bioactive compounds from thinned peach fruits using water as a solvent is an alternative to conventional extraction methods which require dried products, large amounts of organic solvents and long extraction times.This work was supported by the Department of Industry and Innovation of the Aragón Government and the European Social Fund (Project 229402/1 – Plant Food Research Group (T41)).Peer reviewe

The Tuber indicum (Chinese truffle) and Tuber melanosporum (Black truffle) species are morphologically very similar but their aromas are very different. The black truffle aroma is much more intense and complex, and it is consequently appreciated more gastronomically. This work tries to determine whether the differences between the aromatic compounds of both species are sufficiently significant so as to apply them to fraud detection. An olfactometric evaluation (GC-O) of T. indicum was carried out for the first time. Eight important odorants were identified. In order of aromatic significance, these were: 1-octen-3-one and 1-octen-3-ol, followed by two ethyl esters (ethyl isobutyrate and ethyl 2-methylbutyrate), 3-methyl-1-butanol, isopropyl acetate, and finally the two sulfides dimethyldisulfide (DMDS) and dimethylsulfide (DMS). A comparison of this aromatic profile with that of T. melanosporum revealed the following differences: T. indicum stood out for the significant aromatic contribution of 1-octen-3-one and 1-octen-3-ol (with modified frequencies (MF%) of 82% and 69%, respectively), while in the case of T. melanosporum both had modified frequencies of less than 30%. Ethyl isobutyrate, ethyl 2-methylbutyrate and isopropyl acetate were also significantly higher, while DMS and DMDS had low MF (30-40%) compared to T. melanosporum (>70%). The volatile profiles of both species were also studied by means of headspace solid-phase microextraction (HS-SPME-GC-MS). This showed that the family of C8 compounds (3-octanone, octanal, 1-octen-3-one, 3-octanol and 1-octen-3-ol) is present in T. indicum at much higher levels. The presence of 1-octen-3-ol was higher by a factor of about 100, while 1-octen-3-one was detected in T. indicum only (there was no chromatographic signal in T. melanosporum). As well as showing the greatest chromatographic differences, these two compounds were also the most powerful from the aromatic viewpoint in the T. indicum olfactometry. Therefore, either of the two chromatographic methods (GC-O or HS-SPME-GC-MS), together or separately, could be used as a screening technique to distinguish between T. indicum and T. melanosporum and thus avoid possible fraud.

The aim of this work was to elucidate the role of the secondary metabolites produced by B. amyloliquefaciens BUZ-14 against B. cinerea, M. fructicola, M. laxa, P. digitatum, P. italicum and P. expansum both in vitro and in planta. The entire cell free supernatant (CFS) and the lipopeptide fraction (LPF) showed similar antifungal activities, completely inhibiting all the fungi at dilutions of 1:24 or even lower, whereas the non-butanolic fraction (NBF) barely inhibited the fungi. However, when the LPF and CFS were applied on fruit, only brown rot in peaches and blue rot in apples was totally inhibited. The main families of metabolites in the LPF were iturin A, fengycin and surfactin with maximum concentrations of 407, 853 and 658 μg mL-1, respectively. Subsequently, a TLC-bioautography revealed iturin A as the key metabolite in the inhibitions and allowed us to establish in vivo MICs of 16.9 and 33.9 μg mL-1 for Monilinia species and P. expansum, respectively. The application of 24 h-old BUZ-14 cultures suppressed brown rot in peaches and also blue rot in apples but failed to inhibit the other diseases. However, BUZ-14 was only able to grow and produce iturin A in peaches so we can deduce that the amount of iturin A brought with the cultures (36 ± 14 μg mL-1) could be enough to control both diseases. The strong antifungal activity of the iturin A present in the BUZ-14 CFS suggests that it could be successfully used for postharvest disease control. However, future research is necessary to maximize the iturin A production by B. amyloliquefaciens BUZ-14 in order to optimize a commercial application.