The present study was conducted to determine differences in antioxidant levels of fresh, frozen, and freeze-dried strawberries, and strawberry jam. Hydrophilic antioxidant activity (HAA) and lipophilic antioxidant activity (LAA) were measured using the ABTS/H₂O₂/HRP decoloration method. HAA and LAA were then summed to calculate the total antioxidant activity (TAA). Mean differences in HAA and LAA were analyzed using one-way analysis of variance and Dunnett's T3 pairwise comparisons. The mean TAA for freeze-dried strawberries based on an 'as consumed' weight (95% confidence interval [CI]: 29.58, 30.58) was significantly higher than for fresh (95% CI: 3.18, 3.66), frozen (95% CI: 2.58, 2.79), and jam (95% CI: 1.10, 1.22). The mean TAA based on dry weight for fresh strawberries (95% CI: 40.48, 46.67) was significantly higher than for freeze-dried (95% CI: 29.58, 30.58), frozen (95% CI: 24.62, 26.59), and jam (95% CI: 1.48, 1.64). Results agree with previous studies reporting that strawberries are a valuable source of antioxidants for consumers.

The present study examined the effects of domestic cooking methods on the hydrophilic antioxidant activity (HAA) of wild blueberries. Baked, microwaved, simmered, and pan-fried frozen wild blueberries, and a thawed uncooked control, were analyzed for HAA using an ABTS/H(2)O(2)/HRP decoloration method. All cooking treatments were derived from recipes using wild blueberries, and were performed in triplicate. A randomized block design was used to determine whether there were statistical differences in antioxidant content after cooking and between each of the trials. There were no statistically significant decreases after cooking the thawed berries. On both a fresh weight and a dry weight basis, pan-fried blueberries had significantly higher HAA than baked, simmered, and control blueberries (P<0.05). Antioxidants in wild blueberries appear to be heat stable since cooked berries retained significant HAA. Cooked wild blueberries can be recommended as a good source of dietary antioxidants.

The utilization of tissue culture in the propagation and genetic improvement of conifers holds promise of many benefits including faster multiplication of selected genotypes, faster development of improved genotypes and the transfer of genes between non-fertile parents. However, many of the techniques required for the realization of this potential remain to be developed. Furthermore, genetic differentiation of cells in culture creates uncertainty as to the fidelity of reproduction by micropropagation. Aspects of the problem of nuclear DNA variation during reproduction by tissue culture are reviewed with particular reference to the genus Pinus.

Attempts to preserve selected genotypes through clonal propagation may be hampered by genetic instability produced during the tissue culture phase of the propagation procedure. To investigate the genetic condition of loblolly pine (Pinus taeda L.) tissue cultures, nuclear DNA content in embryos grown in vitro and in regenerated buds were examined using two‐wavelength microspectrophotometry. Embryos were grown on chemically defined media containing cytokinin as the sole growth regulator. Nuclear DNA content remained at or between 2 C and 4 C with no evidence of polyploidy during nearly 3 months of continuous culture. Benzylaminopurine, even at concentrations which were supraoptimal for shoot regeneration, had no effect on nuclear DNA content. Regenerated shoots also had stable nuclear DNA contents which correspond to a diploid condition. These results are of significance for the development of mass propagation techniques for this commercially valuable species.

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