Assessment of Fish Oil Oxidation Using Low-Field Proton Nuclear Magnetic Resonance Spectroscopy

Fish oil has been shown to have a variety of health benefits, yet the oil’s component polyunsaturated fatty acids are highly prone to oxidation. In this manuscript, methods to study fish oil oxidation using low-field 1H nuclear magnetic resonance (NMR) spectroscopy were investigated. Fish oil samples in open and closed vials were stored at 25 and 40 °C for 26 days, and signals corresponding to triglycerides and oxidation products were identified and monitored over time. Linear and partial least squares regression (PLSR) were used to model common oxidation metrics, peroxide value and p-anisidine value, and predict sample age. Low-field NMR yielded spectra with lower resolution compared to high-resolution spectra; however, regions corresponding to parts of triglycerides and oxidation products did show meaningful trends, with triglyceride signals generally decreasing and oxidation signals increasing over time. While both model types were effective, linear regression results better summarized the variability of the data, leading to successful predictive models of oxidation metrics compared to PLSR. This study provides preliminary evidence that low-field NMR can be used as a rapid method to assess fish oil oxidation, but more data would be needed to apply this model to other oil samples

Type and Amount of Lipids Influence the Molecular and Textural Properties of a Soy Soft Pretzel

Altering baked goods by the addition of nutrient-rich ingredients, such as soy and ground almonds, affects the water and lipid distribution of the product and, subsequently, its final quality. Here, we studied how three lipid sources, shortening, canola oil, and ground almonds, affected texture and water distribution in a baked soy pretzel and the molecular mobility in the dough. Pretzel crumb from all formulations exhibited 40–43% moisture with a little more than half present as “freezable” water. Firmness and chewiness decreased with increased shortening and canola oil, whereas firmness and chewiness increased with additional almonds. In contrast, neither springiness nor cohesiveness was affected by the lipid quantity or source. Finally, magnetic resonance imaging of the soy pretzel dough revealed two or three populations of dough components that have distinct molecular mobilities. With increased lipid content, the mobility of each population increased in magnitude and heterogeneity. Interestingly, almonds had the smallest effect on the molecular mobility of the dough but had the largest effect on textural properties. These results provide quantitative insight into the mechanisms by which the lipid source can influence molecular properties that have textural implications for bakery products

Tunable Keratin Hydrogels for Controlled Erosion and Growth Factor Delivery

Tunable erosion of polymeric materials is an important aspect of tissue engineering for reasons that include cell infiltration, controlled release of therapeutic agents, and ultimately to tissue healing. In general, the biological response to proteinaceous polymeric hydrogels is favorable (e.g., minimal inflammatory response). However, unlike synthetic polymers, achieving tunable erosion with natural materials is a challenge. Keratins are a class of intermediate filament proteins that can be obtained from several sources, including human hair, and have gained increasing levels of use in tissue engineering applications. An important characteristic of keratin proteins is the presence of a large number of cysteine residues. Two classes of keratins with different chemical properties can be obtained by varying the extraction techniques: (1) keratose by oxidative extraction and (2) kerateine by reductive extraction. Cysteine residues of keratose are “capped” by sulfonic acid and are unable to form covalent cross-links upon hydration, whereas cysteine residues of kerateine remain as sulfhydryl groups and spontaneously form covalent disulfide cross-links. Here, we describe a straightforward approach to fabricate keratin hydrogels with tunable rates of erosion by mixing keratose and kerateine. SEM imaging and mechanical testing of freeze-dried materials showed similar pore diameters and compressive moduli, respectively, for each keratose–kerateine mixture formulation (∼1200 kPa for freeze-dried materials and ∼1.5 kPa for hydrogels). However, the elastic modulus (<i>G</i>′) determined by rheology varied in proportion with the keratose–kerateine ratios, as did the rate of hydrogel erosion and the release rate of thiol from the hydrogels. The variation in keratose–kerateine ratios also led to tunable control over release rates of recombinant human insulin-like growth factor 1

Supplemental Figure S5 from Isoflavone Pharmacokinetics and Metabolism after Consumption of a Standardized Soy and Soy–Almond Bread in Men with Asymptomatic Prostate Cancer

Supplemental Figure S5. Supplemental Figure S5. Prostate specific antigen levels pre-study, during study, and post-study. Mean {plus minus} SEM. Inset reports the slope of average prostate specific antigen values.</p

Supplemental Figure S4 from Isoflavone Pharmacokinetics and Metabolism after Consumption of a Standardized Soy and Soy–Almond Bread in Men with Asymptomatic Prostate Cancer

Supplemental Figure S4. Supplemental Figure S4 Plasma isoflavone levels over a 24 hour period after a single meal with soy bread and soy-almond bread.</p

Supplemental Materials and Methods (S1) from Isoflavone Pharmacokinetics and Metabolism after Consumption of a Standardized Soy and Soy–Almond Bread in Men with Asymptomatic Prostate Cancer

Supplemental Methods details the methods for preparation and standardization of study soy breads and the quantification of isoflavonoids in blood samples</p

Supplemental Table S2 from Isoflavone Pharmacokinetics and Metabolism after Consumption of a Standardized Soy and Soy–Almond Bread in Men with Asymptomatic Prostate Cancer

Supplemental Table S2. Nutrient and isoflavone content of the soy and soy-almond bread consumed and the meals ingested during day one of the pharmacokinetic study</p

Supplemental Table S3 from Isoflavone Pharmacokinetics and Metabolism after Consumption of a Standardized Soy and Soy–Almond Bread in Men with Asymptomatic Prostate Cancer

Supplemental Table S3. Demographic, clinical, and pathological characteristics of 25 men with biochemical recurrent prostate cancer</p

Supplementary Table 1 from Consumption of Soy Isoflavone Enriched Bread in Men with Prostate Cancer Is Associated with Reduced Proinflammatory Cytokines and Immunosuppressive Cells

Mean Differences in Cytokines.</p

Supplementary Table 2 from Consumption of Soy Isoflavone Enriched Bread in Men with Prostate Cancer Is Associated with Reduced Proinflammatory Cytokines and Immunosuppressive Cells

Supplemental Data Table 2A and 2B to describe changes in cytokine and cellular biomarkers between soy and soy-almond bread.</p