By Berta Baca-Bocanegra, José Miguel Hernández-Hierro, Francisco José Heredia, Julio Nogales-Bueno

The levels of extractable phenolic compounds of red grapes (Vitis vinifera L.) vary considerably. Currently, interest has shifted to the development of portable vis/NIR systems, innovation in optical system design and miniaturization for its approachable use in the field. In 2016 and 2017 vintages, spectra of intact grapes and grapes skins were recorded at harvest time using a portable micro NIR spectrophotometer. Several chemometric approaches have been used for spectral interrogation and evaluation of the device. Spectral data have been correlated with red grape skin extractable polyphenols. It was concluded that several factors affect the use of the portable micro NIR device for the “in vineyard” screening of extractable polyphenols in red grape skins. Environmental and physiological conditions should be considered to evaluate and remove factors that hamper a good sorting the berries according to their extractable polyphenol contents. Find out more

By Suzy Rogiers and Francesca Moroni

Evidence for chronobiology can be found in many aspects of viticulture. Buds swell and burst every spring with warmer temperatures and longer days. The onset of flowering is also driven by changes in day length and its timing is important to reproductive success. Grapevines can sense longer days in spring through the light receptors located in green tissues. Alternatively, leaf senescence is activated as day length shortens in autumn and the vine prepares for dormancy. Co-ordination between cells and tissues of the shoot tips, leaves, woody components and roots is critical to successful regulation of growth and development. This may explain the presence of multiple clocks in different tissue types within any one organism. Find out more

By Astrid Buica and Marianne McKay

The odor detection threshold (ODT) of a compound is the lowest concentration at which individuals can reliably perceive a difference between a sample and its corresponding control, with 50% performance above chance. Wine is a complex matrix, and ODTs used in studies on wine can be based on inappropriate matrices and informal sensory methodologies. This post reports a study where the sensitivity of panelists to previously published ODTs for five compounds were tested. Results showed that, despite some limitations, this pragmatic approach may be useful when carrying out sensory studies with limited resources and within tight timelines, as it provides helpful information on panel members and detection thresholds for a specific matrix Find out more