Hugh A. Daubeny

Sensory, chemical and gas chromatographic evaluation of five raspberry cultivars

Abstract Five raspberry cultivars, ‘Chilcotin’, ‘Chilliwack’, ‘Meeker’, ‘Skeena’ and ‘Tulameen’, were evaluated for sensory attributes, and chemical and flavor volatile compounds. ‘Chilliwack’ and ‘Tulameen’ received high ratings in sweetness and overall impression with high soluble solids, total sugars and sugar:acid ratio. ‘Chilcotin’ rated low in overall impression and sweetness, and high in sourness and astringency, with low soluble solids, sugar:acid ratio and total sugars, and high titratable acidity. Principal factor analysis (PFA) of the sensory results separated the cultivars based on desirable (appearance, color, texture, aroma and sweetness) and less desirable (sourness, bitterness, astringency and off-flavor) attributes. Twenty-eight volatile compounds were analyzed by dynamic headspace and 18 identified by gas chromatography-mass spectrometry (GC-MS), most of which were terpenes which included α-pinene, sabinene, γ-terpinene, α- and β-ionone and caryophyllene. Volatile compounds varied among cultivars, with benzaldehyde (11·1–31·8%), α-pinene (4·0–11·5%), ethyl heptanoate (6·9–15·2%), β-myrcene (13·2–19·6%) and γ-terpinene (12·2–20·0%) as the predominant volatiles. Correlation analysis established no relationships between sensory and chemical data with volatile compounds.

BLOSSOMING TREASURES OF BIODIVERSITY: 1. Stevia (Stevia rebaudiana (Bertoni) Bertoni)—how sweet it is!

The Plant: Stevia (named for P.J. Esteve, a 16th century Spanish botanist) is a herbaceous, or semi-woody, shrublike plant to 1 m tall. A member of the sunflower family, it produces small white flowers with a pale purple throat, and seeds like those of dandelions. The shoots generally die after seeding, but this perennial plant reproduces well in the spring from new shoots from its base. Stevia is most notable for its production of sweet chemicals that add no calories to one’s diet, with some being more than 300 times as sweet as sugar.