European legislation overall agrees that apple juice concentrate is allowed to be used to some extent in cider production. However, no comprehensive research is available to date on the differences in suitability for fermentation between fresh apple juice and that of reconstituted apple juice concentrate. This study aimed to apply freshly pressed juice and juice concentrate made from the same apple cultivar as a substrate for cider fermentation. Differences in yeast performance in terms of fermentation kinetics and consumption of nutrients have been assessed. Fermented ciders were compared according to volatile ester composition and off-flavor formation related to hydrogen sulfide. Based on the results, in the samples fermented with the concentrate, the yeasts consumed less fructose. The formation of long-chain fatty acid esters increased with the use of reconstituted juice concentrate while the differences in off-flavor formation could not be determined. Overall, the use of the concentrate can be considered efficient enough for the purpose of cider fermentation. However, some nutritional supplementation might be required to support the vitality of yeast.

Until now, cheese peptidomics approaches have been criticised for their lower throughput. Namely, analytical gradients that are most commonly used for mass spectrometric detection are usually over 60 or even 120 min. We developed a cheese peptide mapping method using nano ultra-high-performance chromatography data-independent acquisition high-resolution mass spectrometry (nanoUHPLC-DIA-HRMS) with a chromatographic gradient of 40 min. The 40 min gradient did not show any sign of compromise in milk protein coverage compared to 60 and 120 min methods, providing the next step towards achieving higher-throughput analysis. Top 150 most abundant peptides passing selection criteria across all samples were cross-referenced with work from other publications and a good correlation between the results was found. To achieve even faster sample turnaround enhanced DIA methods should be considered for future peptidomics applications.

Several studies have shown the ability of yeast to consume peptides as a nitrogen source in single-peptide containing media. However, a suitable and cost-effective methodology to study the utilization of peptides by yeast and other microorganisms in a complex peptide mixture has yet to be put forward. This article addresses this issue by presenting a screening methodology for tracking the consumption of peptides by yeast during alcoholic fermentation. As a peptide source, the methodology makes use of an in-house prepared peptide-mapped bovine serum albumin (BSA) proteolytic digest, which was applied to a synthetic grape must. The peptide uptake was analyzed using high-throughput ultra-high-pressure liquid chromatography coupled to data-independent acquisition-based ion mobility separation-enabled high-resolution mass spectrometry (UPLC-DIA-IMS-HRMS) analysis. The relative changes of abundance of 123 di- to hexapeptides were monitored and reported during fermentations with three commercial wine strains, demonstrating different uptake kinetics for individual peptides. Using the same peptide-mapped BSA hydrolysate, the applicability of an untargeted workflow was additionally assessed for peptide profiling in unelucidated matrixes. The comparison of the results from peptide mapping and untargeted analysis experiments highlighted the ability of untargeted analysis to consistently identify small molecular weight peptides on the length and amino acid composition. The proposed method, in combination with other analytical techniques, such as gene or protein expression analysis, can be a useful tool for different metabolic studies related to the consumption of complex nitrogen sources by yeast or other microorganisms.