Lactobacillus species are prominent inhabitants of the human gastrointestinal tract that contribute to maintaining a balanced microbial environment that positively influences host health. These bacterial populations can be altered through use of probiotic supplements or via dietary changes which in turn affect the host health. Utilizing polyphenolic compounds to selectively stimulate the growth of commensal bacteria can have a positive effect on the host through the production of numerous metabolites that are biologically active. Four Lactobacillus strains were grown in the presence of pomegranate (POM) extract. Two strains, namely, L. acidophilus NCFM and L. rhamnosus GG, are commonly used probiotics, while the other two strains, namely, L. crispatus NCK1351 and L. gasseri NCK1342, exhibit probiotic potential. To compare and contrast the impact of POM on the strains' metabolic capacity, we investigated the growth of the strains with and without the presence of POM and identified their carbohydrate utilization and enzyme activity profiles. To further investigate the differences between strains, an untargeted metabolomic approach was utilized to quantitatively and qualitatively define the metabolite profiles of these strains. Several metabolites were produced significantly and/or exclusively in some of the strains, including mevalonate, glutamine, 5-aminoimidazole-4-carboxamide, phenyllactate, and fumarate. The production of numerous discrete compounds illustrates the unique characteristics of and diversity between strains. Unraveling these differences is essential to understand the probiotic function and help inform strain selection for commercial product formulation.

Trehalose crystals exhibit polymorphic, deliquescent, and hydrate‐forming traits and can exist in dihydrate, β‐anhydrate, or α‐anhydrate (isomorphic desolvate) forms. The objective of this study was to identify the relative humidity (RH) and temperature boundaries for phase changes of these different trehalose crystal forms. The deliquescence points (RH0s) of the anhydrate and dihydrate trehalose crystals were determined from 20 to 50 °C using a combination of water activity and dynamic vapor sorption measurement techniques. Increasing temperatures from 20 to 50 °C resulted in decreases in RH0 from 95.5% to 90.9% RH for the dihydrate and 69.9% to 62.0% RH for the β‐anhydrate. The effects of temperature on the anhydrate–hydrate RH boundaries were also determined, using a combination of equilibration in controlled water activity solutions, powder X‐ray diffraction, and Fourier‐transform infrared spectroscopy techniques. Increasing temperatures resulted in increases in the anhydrate–hydrate RH boundaries. The irreversible β‐anhydrate to dihydrate boundary increased from 44.9% to 57.8% RH, and the reversible α‐anhydrate to dihydrate boundary increased from 10% to 25% RH, as temperature increased from 20 to 50 °C. This is the first report of an RH–temperautre stability map for crystalline trehalose. Practical Application The manuscript addresses the issue of the physical stability and phase transformations of crystalline trehalose stored in different temperature and relative humidity environments. Unwanted hydrate formation or dehydration of crystal hydrates can lead to other undesirable water–solid interactions and/or physical modifications that have the potential to influence product quality and delivery traits. Therefore, this study identified relative humidity and temperature stability boundaries of the different trehalose crystal forms, using a variety of established and novel techniques to create a relative humidity–temperature stability map of crystalline trehalose from 20 to 50 °C.

The gelatinization temperature (Tgel) of starch increases in the presence of sweeteners due to sweetener-starch intermolecular interactions in the amorphous regions of starch. Different starch botanical sources contain different starch architectures, which may alter sweetener-starch interactions and the effects of sweeteners on Tgels. To document these effects, the Tgels of wheat, potato, waxy corn, dent corn, and 50% and 70% high amylose corn starches were determined in the presence of eleven different sweeteners and varying sweetener concentrations. Tgels of 2:1 sweetener solution:starch slurries were measured using differential scanning calorimetry. The extent of Tgel elevation was affected by both starch and sweetener type. Tgels of wheat and dent corn starches increased the most, while Tgels of high amylose corn starches were the least affected. Fructose increased Tgels the least, and isomalt and isomaltulose increased Tgels the most. Overall, starch Tgels increased more with increasing sweetener concentration, molar volume, molecular weight, and number of equatorial and exocyclic hydroxyl groups. Starches containing more short amylopectin chains, fewer amylopectin chains that span through multiple clusters, higher number of building blocks per cluster, and shorter inter-block chain lengths exhibited the largest Tgel increases in sweetener solutions, attributed to less stable crystalline regions.