Non-destructive evaluation of checking in thermally modified timber

Non-destructive measurement techniques were used to study the characteristics of thermally modified timber (TMT), especially checking. Two non-destructive measurement techniques were evaluated: air-coupled ultrasound (ACU) and electrical impedance spectroscopy (EIS). In the studied TMT (N = 38), density and pith location in the cross-section were positively correlated with the number of checks in the cross-section. Several ultrasound signal features correlated with TMT characteristics, most strongly with number of checks. Severely checked samples and other samples were considered as two different classes of checking, and the potential of ultrasound for differentiating between the two classes was tested by using Bayesian classification method. The correct classification rate was 97 %. EIS parameters correlated with density and latewood content of TMT more strongly than the ACU parameters. Thus, for determination of checking and density or earlywood/latewood content, both EIS and ACU measurements are recommended.     

Determination of volatile organic compound patterns characteristic of five unifloral honey by solid-phase microextraction-gas chromatography-mass spectrometry coupled to chemometrics

We report the evaluation of the floral origin of honey by analysis of its volatile organic compounds (VOCs) profile, joined with the use of combined pattern recognition techniques. Honey samples, from five floral origins, were analyzed by headspace solid-phase microextraction-gas chromatography-mass spectrometry, selecting 35 VOCs out of the entire profiles, which were analyzed by hierarchical cluster analysis (HCA), stepwise discriminant analysis (SDA), and K-nearest-neighbor (KNN). Both HCA and SDA were used as exploratory tools to select a group of VOCs representing similitude and differences among studied origins. Thus, six out of 35 VOCs were selected, verifying their discriminating power by KNN, which afforded 93% correct classification. Therefore, we drastically reduced the amount of compounds under consideration but kept a good differentiation between floral origins. Selected compounds were identified as octanal, benzeneacetaldehyde, 1-octanol, 2-methoxyphenol, nonanal, and 2-H-1-benzopyran-2-one. The analysis of VOC profiles, coupled to HCA, SDA, and KNN, provides a feasible alternative to evaluate the botanical source of honey.     

Optimization of the extraction of antioxidants from Dunaliella salina microalga by pressurized liquids

In this work, extraction of antioxidant compounds from Dunaliella salina microalga is optimized by combining pressurized liquid extraction (PLE) and experimental design (three-level factorial design) with three different solvents (hexane, ethanol, and water). Two main factors were considered, the extraction temperature (40, 100, and 160 degrees C) and the extraction time (5, 17.5, and 30 min). As response variables, the extraction yield (percent dry weight/initial weight) and the antioxidant activity of the extracts (determined using the TEAC method) were used. The parameters of the model were estimated by multiple linear regression. Results showed that the extraction temperature was the factor having the strongest influence (positive) on the two response variables. The best yields were obtained with ethanol at the higher extraction temperature and time tested. Besides, although hexane extracts provided the best antioxidant activity, ethanol extracts were also very active. The chemical characterization of ethanol extracts was carried out using HPLC-DAD, and attempts have been made to correlate their chemical composition with the antioxidant activity measured. Results pointed out that the extracts contained, besides all-trans-beta-carotene and isomers, several different minor carotenoids that seemed to make a contribution to the antioxidant activity of the extracts.     

Genetic basis of long shelf life and variability into Penjar tomato

Penjar tomato is a varietal type cultivated in northeast Spain that characteristically has a long shelf life, small fruit, and wide morphological variability among cultivars. To determine the genetic basis for the long shelf life in the Penjar varietal type and to describe the genetic background and agromorphologic characteristics of the group, we studied 27 Penjar accessions representative of the entire range of variation in traits related to agronomic behavior, fruit morphology, and sensory quality. We found that the long shelf life of Penjar (mean: 126.8 days) is due to the ripening mutant alcobaça (alc), and the molecular basis of this mutation is the replacement of thymine by adenine in position 317 of the coding sequence of the NAC.NOR gene; thus, alcobaça (alc) is an allele of non-ripening (nor). The amplified fragment length polymorphism (AFLP) study found 18.07% polymorphic loci within the Penjar varietal type, which is higher than usual in landraces. The variation in agronomic and morphologic traits between accessions was also very high; thus, the heterogeneity of the Penjar group probably results from the introduction of the allele alc in distinct landraces. Our results also show that in germplasm containing the alc mutation shelf life is negatively correlated with fruit size (weight, width, length, and number of locules); thus, the predominance of small fruit within the varietal type is probably the result of this trait being dragged along in the selection for long shelf life.