Impact of Saccharomyces cerevisiae and lactic acid bacteria co- and sequential inoculation on the aroma profile of New Zealand Pinot noir wines

Abstract

The use of Lactiplantibacillus plantarum as a malolactic starter in New Zealand Pinot Noir production is a relatively recent development, and its sensory impact compared to the more established choice of Oenococcus oeni remains underexplored. This study investigated the effects of two commercial lactic acid bacterial (LAB) strains on the formation of aroma-active compounds and sensory characteristics in New Zealand Pinot Noir wines. The research compares co-inoculation and sequential inoculation of wine yeast and LAB, with samples collected at four timepoints throughout fermentation. In addition to the chemical analysis of volatile compounds, sensory evaluation was conducted using Napping and Check-All-That-Apply (CATA). Aroma development was found to be non-linear, with mid-fermentation representing a key transition stage in volatile evolution. Co-inoculation consistently resulted in fruitier and more floral wines. Sequential inoculation, by contrast, produced more developed aromatic profiles. Notably, wines produced under the same inoculation regime, regardless of which LAB strain was used, showed highly similar chemical and sensory profiles, suggesting that strain-specific effects were minimal under controlled conditions. Instead, the timing of LAB addition emerged as the dominant factor shaping aroma profiles. These findings provide practical guidance to winemakers on how the timing of bacterial inoculation affects aroma development.