Lay and scientific categorizations of new breeding techniques: Implications for food policy and genetically modified organism legislation.

The rapid development of new genetic breeding techniques is accompanied by a polarized debate around their risks. Research on the public perception of these techniques lags behind scientific developments. This study tests a method for revealing laypeople's perceptions and attitudes about different genetic techniques. The objectives are to enable laypeople to understand the key principles of new genetic breeding techniques and to permit a comparison of their modes of classification with those of scientific experts. The combined method of a free sorting task and focus groups showed that the participants distinguished the techniques that did not induce any change in DNA sequence, and applied two different logics to classify the other breeding techniques: a Cartesian logic and a naturalistic logic with a distinct set of values. The lay categorization differed substantially from current scientific categorizations of genetic breeding techniques. These findings have implications for food innovation policy and genetically modified organism legislation.

Use of random forest methodology to link aroma profiles to volatile compounds: Application to enzymatic hydrolysis of Atlantic salmon (Salmo salar) by-products combined with Maillard reactions.

To use salmon protein hydrolysates as food ingredients and to mask the fish odor, Maillard reactions were associated with enzymatic production of hydrolysates. The study explored an original approach based on regression trees (RT) and random forest (RF) methodologies to predict hydrolysate odor profiles from volatile compounds. An experimental design with four factors: enzyme/substrate ratio, quantity of xylose, hydrolysis and cooking times was used to create a range of enzymatic hydrolysates. Twenty samples were submitted to a trained panel for sensory descriptions of odor. Hydrolysate volatile compounds were extracted by means of Headspace Solid Phase MicroExtraction (HS-SPME) and analyzed using gas chromatography/mass spectrometry (GC-MS). The results showed that RT and RF methodologies can be useful tools for predicting an entire sensory profile from volatile compounds. Four main volatile compounds made it possible to separate hydrolysates into five groups according to their specific sensory profile. 2,5-dimethylpyrazine, 1-hydroxy-2-propanone and 3-hydroxy-2-pentanone were identified as the main predictors of the roasted odor, whereas methanethiol was associated with a mud odor. These results also suggest the appropriate process conditions for obtaining a typical roasted odor.

Proteolysis of Sardine (Sardina pilchardus) and Anchovy (Stolephorus commersonii) by Commercial Enzymes inSaline Solutions.

Fish sauce production is a very long process and there is a great interest in shortening it. Among the different strategies to speed up this process, the addition of external proteases could be a solution. This study focuses on the effect of two commercial enzymes (Protamex and Protex 51FP) on the proteolysis of two fish species traditionally converted into fish sauce: sardine and anchovy, by comparison with classical autolysis. Hydrolysis reactions were conducted with fresh fish at a temperature of 30 °C and under different saline conditions (from 0 to 30% NaCl). Hydrolysis degree and liquefaction of the raw material were used to follow the process. As expected, the proteolysis decreased with increasing amount of salt. Regarding the fish species, higher rate of liquefaction and higher hydrolysis degree were obtained with anchovy. Between the two proteases, Protex 51FP gave better results with both fish types. This study demonstrates that the addition of commercial proteases could be helpful for the liquefaction of fish and cleavage of peptide bonds that occur during fish sauce production and thus speed up the production process.

Influence of temperature, pH and NaCl concentration on the maximal growth rate of Brochothrix thermosphacta and a bioprotective bacteria Lactococcus piscium CNCM I-4031.

The maximum specific growth rate (µ(max)) of Brochothrix thermosphacta, a spoilage bacteria of cooked peeled shrimp, and Lactococcus piscium CNCM I-4031, a bioprotective strain, was investigated under different conditions of temperature, NaCl concentrations and pH. The basic modelling approach used was the Gamma concept (γ-concept) and the model developed was then adapted to shrimp. Cardinal growth parameters were quite similar for the two strains, except for NaCl. No NaCl was required for growth and the NaCl(max) was three-times higher for B. thermosphacta than for L. piscium (62 and 23 g l(-1) respectively). However, tolerance to NaCl was higher in seafood than in liquid broth, possibly due to presence of osmoltically active molecules. L. piscium and B. thermosphacta were psychrotolerant, with T(min) = -4.8 and -3.4 °C, T(opt) = 23.4 and 27.0 °C and T(max) = 27.2 and 30.8 °C respectively. The optimal pH was neutral and growth possible till pH = 4.8 for the two strains, assuming possible applications of the bioprotective strain in lightly marinated seafood. The µ(max) of B. thermosphacta in shrimp was a little higher than in L. piscium whatever the environmental conditions. Validation of the model showed that the γ-concept was suitable for predicting µ(max) of B. thermosphacta in shrimp. Data generated in this study can be used to adapt the model to other foods with few additional experiments and the effect of different parameters may be added in the future. The model was less accurate for the bioprotective strain and the effect of NaCl must be studied in more detail directly in the matrix.

Influence of Crassostrea gigas (Thunberg) sexual maturation stage and ploidy on uptake of paralytic phycotoxins.

The purpose of this study was to assess paralytic phycotoxin uptake in diploid and triploid oysters at two stages of their sexual cycle corresponding to their status in early summer (June) and winter (November). Samples of diploid and triploid oysters were exposed to a toxic culture of Alexandrium minutum for 4 days in each season. No significant differences in filtration or clearance rates were observed during either November or June experiments. When diploid oysters were at resting stage (November), toxin uptake showed no significant difference between the ploidy classes. In contrast, when the diploid oysters were at the peak of their sexual maturation (June), the triploid oysters were seen to accumulate almost double the amount of paralytic toxins as the diploid ones.

DECREASE IN DYNAMIC VISCOSITY AND AVERAGE MOLECULAR WEIGHT OF ALGINATE FROM LAMINARIA DIGITATA DURING ALKALINE EXTRACTION(1).

Alginates are natural polysaccharides that are extracted from brown seaweeds and widely used for their rheological properties. The central step in the extraction protocol used in the alginate industry is the alkaline extraction, which requires several hours. In this study, a significant decrease in alginate dynamic viscosity was observed after 2 h of alkaline treatment. Intrinsic viscosity and average molecular weight of alginates from alkaline extractions 1-4 h in duration were determined, indicating depolymerization of alginates: average molecular weight decreased significantly during the extraction, falling by a factor of 5 between 1 and 4 h of extraction. These results suggested that reducing extraction time could enable preserving the rheological properties of the extracted alginates.