Djamila Rekika

Phenolic Composition and Antioxidant Capacity of Newly Developed Strawberry Lines from British Columbia and Quebec

The total phenolic composition (TPC) and the total antioxidant capacity (TAC) of eleven strawberry genotypes selected from the AAFC breeding program (BC2-72-17, BC2-90-43, BC96-33-4 and BC98-49-34 from British Columbia; and APF937-1, APF939-71, LL981-24, LL9819-14, LL982-14, LL0220-10 and SJ9332-7 from Quebec) were evaluated using high-performance liquid chromatography (HPLC) and ferric reducing/antioxidant power (FRAP) assays. TPC and TAC values of these genotypes were compared to those of four commercially grown cultivars (‘Chambly,’ ‘Kent,’ ‘Veestar’ and ‘Yamaska’) and the effects on fruit quality and shelf life were studied. Several groups of phenolic compounds, including anthocyanins, flavonols, hydroxycinnamic, ellagic and benzoic acids, were identified and quantified by HPLC. Significant variation of TPC was observed between genotypes, and anthocyanins were found to be the predominant phenolic group, contributing to 79.2% of the TPC. A significant correlation (r = 0.96) was observed between TPC and anthocyanin content. BC2-72-17 had the highest anthocyanin content and differed significantly from the other genotypes. Although the highest TPC (2123.8 μg g−1) was found in BC2-72-17, this genotype did not have the highest antioxidant capacity. The highest TAC (2259.0 μg g−1) was found in BC2-90-43, indicating that other phenolics may have made a greater contribution than anthocyanins to the high TAC. At room temperature, LL0220-10, SJ9332-7 and ‘Yamaska’ had a three-day shelf life, while it was only two days for all other genotypes. There was a negative correlation between shelf life and ellagic acids, flavonol and anthocyanin levels but this relationship was not significant (p > 0.0.). The fruit soluble solids content (SSC) and titratable acidity (TA) varied between genotypes. ‘Veestar’ and LL981-24 had the highest SSC (7.5). These results point to the importance of identifying genotypes with high phenolic monomer activities in screening for lines with high TAC, to ensure their use in breeding programs aimed at improving the nutritional value of strawberry.

Agronomic characteristics and chemical composition of newly developed day-neutral strawberry lines by Agriculture and Agri-Food Canada.

The agronomic characteristics and chemical composition of seven advanced day-neutral strawberry lines and a commercial cultivar ‘Seascape’ were evaluated for their horticulture and quality attributes. The results showed that the advanced strawberry lines had the best horticultural characteristics, such as more resistance to diseases, less weight and juice losses and better fruit glossiness during storage, compared to ‘Seascape’. Among the advanced lines, FIN005–55 had the better fruit quality with higher soluble solids content (SSC)/titratable acidity (TA) ratio and highest SSC, FIN005–7 had the highest total phenolic content (TPC) and antioxidant capacity (AC), and both had potential for commercial trials.

The Use of a Bud Freezing Technique to Determine the Hardiness of 20 Grape Genotypes

Abstract Pencil thick canes (-8 mm) from 20 different grape cultivars were harvested at 2 different dates in the fall (October and November). The cultivars had previously been classified as hardy (group A), semi-hardy (group B) or tender (group C). Individual bud sections of the canes were placed in a refrigeration unit and subjected to sequential freezing temperatures of 19°F, 5°F, −8°F and −22°F (−7°C, −15°C, −22°C, and −30°C) for 24 hours at each temperature. Samples were removed each day to evaluate the survival of buds. Results for the samples taken in October showed that almost 100% of the buds were killed once they were subjected to −8°F (−22°C) or colder. The critical temperature appeared to be 5°F (−15°C), where there was a marked difference in survival between the 3 groups of genotypes: percent mortality was 46%, 68% and 94% for groups A, B, and C, respectively. In November, most of the hardy cultivars showed little adverse effects at −8°F (−22°C), whereas the tender cultivars suffered the most injury with percent mortality of 25% and 83%, respectively.

Soluble Solids, Acidity, Canopy Fruit Distribution, and Disease Susceptibility of Selected Grape Cultivars in Quebec

ABSTRACT Twenty grapevine genotypes (‘Chancellor’, ‘Delisle’, ‘ES-6–12–28’, ‘ES-4–7–25’, ‘GR-7’, ‘Hibernal’, ‘Sabrevois’, ‘Kay Gray’, ‘Lucie Kuhlmann’, ‘Michurinetz’, ‘Okanagan Riesling’, ‘Prairie Star’, ‘St. Croix’, ‘St. Pepin’, ‘Seyval Noir’, ‘Seyval Blanc’, ‘SV-18–307’, ‘Vandal-Cliche’, ‘Vidal Blanc’, and ‘Siegerrebe’) were evaluated under different winter protection methods in Frelighsburg, Quebec, Canada. The effects of these methods on soluble solids, acidity, fruit canopy distribution, and susceptibility to diseases were evaluated. Significant differences in juice composition was observed among the tested cultivars, and a significant interaction was observed between cultivar and sampling date, indicating that the effects of sampling date and cultivar are not independent. SSC/acid ratio increased with a corresponding decrease in acidity and the hardy and semi-hardy cultivars Lucie Kuhlmann, Michurinetz, and Geneva Red produced the highest °Brix values. None of the tender cultivars had values exceeding 19.5 °Brix. A decrease in acidity was observed for all cultivars as ripening progressed except for ‘Seyval Blanc’, ‘St. Pepin’, ‘St. Croix’, and ‘SV-18307’, which showed little or no reduction in acidity during the last three sampling dates. Under the climatic conditions observed in this study, ‘Prairie Star’, ‘ES-4–7–25’, ‘Geneva Red’, ‘St. Pepin’, ‘Delisle’, ‘ES-6–12–28’, ‘Vandal Cliche’, ‘Kay Gray’, ‘Lucie Kuhlmann’, ‘Okanagan Riesling’, and ‘SV-18–307’ had acceptable SSC and TA values. No clusters were observed at a wire level above 175 cm in any of the winter protection systems. In the M1 and M2 treatments, almost all the cultivars produced the highest proportion of clusters at a height of 80 to 125 cm and minimum fruit clusters close to the ground. Unlike the M1 and M2 methods, the M3 winter protection approaches produced a wide distribution of fruit in the canopy. ‘Michurinetz’ had the highest powdery mildew infection, followed by ‘Siegerrebe’ and ‘Lucie Kuhlmann’, whereas ‘Prairie Star’, ‘ES 4–7–25’, ‘St. Croix’, ‘St. Pepin’, ‘Vandal Cliche’, ‘Hibernal’, ‘Okanagan Riesling’, and ‘Seyval Noir’ exhibited low susceptibility. No powdery mildew symptoms were noted in ‘Sabrevois’, ‘Delisle’, ‘Kay Gray’, ‘ES-6–12–28’, ‘Chancellor’, ‘SV-18307’, or ‘Seyval Blanc’.

Evaluation of the Drip Loss of 30 Cultivars and 9 Advanced Selections from Agriculture and Agri-Food Canada National Strawberry Breeding Program

Abstract Fruits of thirty-nine strawberry genotypes were evaluated for their freezing performance based on their drip loss percentage. The amount juice lost was evaluated for each genotype after four months of storage (at — 20°C) upon thawing at 20°C for 20 hr. A preliminary selection based on the drip loss method or exudation enabled us to eliminate genotypes that are the least interesting from a freezing standpoint and to focus our efforts on those with a high processing potential. ‘NY1529’, ‘Scott’, ‘Arking’, ‘SJ8317-5’ and ‘SJ83145-1’ with less than 30% juice loss seems suitable for jam, yogurt and frozen food production. On the other hand, with more than 60% juice loss, ‘Tenira’, ‘Primela’ and ‘Splendida’ seem less desirable for processing.