The effect of the harvest time on oil-based bioactive compounds in sea buckthorn berries ( Hippophae rhamnoides L. ssp. sinensis) was investigated. Sea buckthorn berries were collected at early maturity (September), maturity (November), and postmaturity (January) during the 2003-2004 harvest year. Whole berries were analyzed for physical characteristics, and fruit and seed fractions were analyzed for bioactive content. November-harvested berries yielded the highest values for berry sizes, CIELab factor a*, and total carotenoid content in the fruit fraction ( p < 0.05). September yielded significantly higher ( p < 0.05) levels of major compounds, alpha-tocopherol and beta-sitosterol, in the fruit fraction. Seed characteristics and bioactive compounds did not vary significantly with respect to the harvest time ( p > 0.05). These results have identified the most suitable level of maturity for the optimization of certain compounds and the losses that may occur with winter harvest, commonly practiced in cold climates.

A semi-empirical model was developed for the drying of press cake on an inert sphere in the spout region of a dryer. The coefficients for the Lewis and Page (for the prediction of moisture ratio) and the Chung-Pfost (for the prediction of equilibrium moisture content) models were determined experimentally. The predicted temperature of the press cake was validated using three trials conducted at drying conditions (temperature, relative humidity): 55 C, 55%; 65 C, 45%; and 75 C, 43%. Predicted temperatures were within $10% of the experimental temperatures. Improved prediction accuracy was achieved as press cake temperature approached air temperature.

Sea buckthorn (Hippophae rhamnoides L. ssp. sinensis) berry press cake was dried under forced air convective conditions at three temperature and two relative humidity (RH) levels: 50C at 30.6 and 58.7%, 60C at 24.4 and 57% and 70C at 20.8 and 57%. Seedless press cake (pulp/peel) was analyzed for color, moisture content, water activity and biologically active compounds (carotenoids, fatty acids, tocols and phytosterols). Total carotenoid and phytosterol concentration remained relatively stable. Fatty acid composition also remained relatively stable with only minimal changes to palmitoleic acid at 70C. The lowest color degradation (ΔE = 2.0), was provided by drying conditions of 60C at 24.4% RH, whereas highest concentrations of major tocols occurred at the 50C temperature level. Significant darkening (P < 0.05) occurred at the higher RH level for each temperature. Although the darkening did not represent a loss in carotenoids, it did coincide with a retention/regeneration of tocols. PRACTICAL APPLICATIONS Convective drying is a fundamental operation in the processing of many food products associated with offering health benefits. There has been significant research in the area of physical characteristics of convectively dried food and quality of water‐based compounds. However, there is a lack of research into the stability and quality of oil‐based compounds. This research was developed to contribute to the knowledge base on how convective drying conditions can impact multiple oil‐based compounds within a product suitable for further use by the functional food and nutraceutical industries. Analyzing many compounds together can provide insight into how different bioactive compounds react to the same conditions. This research can also offer opportunity in the development of valuable commodities from an industry by‐product.