Improved recovery of higher boiling point volatiles during solvent-assisted flavour evaporation

Previously published data show that high levels of fat (50%) affect the yield of volatile compounds during solvent-assisted flavour evaporation (SAFE). We present new data demonstrating that even low levels of fat (< 10%) lead to significantly lower yields of high boiling point volatiles during SAFE. Relative recovery during SAFE of a range of volatiles from a cheese extract was measured at varying fat concentrations (1.1–8.7%) using a single internal standard. Volatiles with higher boiling points had significantly lower relative recoveries, and volatiles were substantially less well recovered from higher fat extracts. When endeavoring to obtain solvent extracts of fatty foods for the purposes of GC-O, it is important to choose the extraction technique which produces solvent extracts closely representing the true composition of the food. We present dilution of solvent extracts prior to SAFE as a potential new approach for high-fat foods which enables high yields of volatiles regardless of boiling point. These data also show that in the absence of C13-labelled standards for quantitation, it is critical to maintain a consistent fat content between samples during SAFE

Online, Continuous Sensor and Method for Curd Moisture Content Control in Cheese Making

A method is provided for improving quality of cheese produced from a milk batch. A light beam from an incident light source impinges onto a surface of the milk batch, and light backscatter is optically detected during a coagulation process and correlated to an optimum cutting time for the milk coagulum. Next, light backscattered from a curd and whey mixture derived from the milk batch during a syneresis process is optically detected and correlated to an optimum syneresis endpoint. At least one of the backscattered light data, optical parameters developed from analysis of the backscattered light data, and whey fat dilution are correlated to at least one of a milk protein %, a milk fat %, a milk total solids content, a milk processing temperature, a curd moisture content, a curd moisture change over time, whey fat content, a whey fat loss, and a final curd yield

Reformulation initiative for partial replacement of saturated with unsaturated fats in dairy foods attenuates the increase in LDL cholesterol and improves flow-mediated dilatation compared with conventional dairy: the randomized, controlled REplacement of SaturatEd fat in dairy on Total cholesterol (RESET) study

Background Modifying dairy fat composition by increasing the MUFA content is a potential strategy to reduce dietary SFA intake for cardiovascular disease (CVD) prevention in the population. Objectives To determine the effects of consuming SFA-reduced, MUFA-enriched (modified) dairy products, compared with conventional dairy products (control), on the fasting cholesterol profile (primary outcome), endothelial function assessed by flow-mediated dilatation (FMD; key secondary outcome), and other cardiometabolic risk markers. Methods A double-blind, randomized, controlled crossover 12-wk intervention was conducted. Participants with a 1.5-fold higher (moderate) CVD risk than the population mean replaced habitual dairy products with study products (milk, cheese, and butter) to achieve a high-fat, high-dairy isoenergetic daily dietary exchange [38% of total energy intake (%TE) from fat: control (dietary target: 19%TE SFA; 11%TE MUFA) and modified (16%TE SFA; 14%TE MUFA) diet]. Results Fifty-four participants (57.4% men; mean ± SEM age: 52 ± 3 y; BMI: 25.8 ± 0.5 kg/m2) completed the study. The modified diet attenuated the rise in fasting LDL cholesterol observed with the control diet (0.03 ± 0.06 mmol/L and 0.19 ± 0.05 mmol/L, respectively; P = 0.03). Relative to baseline, the %FMD response increased after the modified diet (0.35% ± 0.15%), whereas a decrease was observed after the control diet (−0.51% ± 0.15%; P< 0.0001). In addition, fasting plasma nitrite concentrations increased after the modified diet, yet decreased after the control diet (0.02 ± 0.01 μmol/L and −0.03 ± 0.02 μmol/L, respectively; P = 0.01). Conclusions In adults at moderate CVD risk, consumption of a high-fat diet containing SFA-reduced, MUFA-enriched dairy products for 12 wk showed beneficial effects on fasting LDL cholesterol and endothelial function compared with conventional dairy products. Our findings indicate that fatty acid modification of dairy products may have potential as a public health strategy aimed at CVD risk reduction. This trial was registered at clinicaltrials.gov as NCT02089035

Food chain approach to lowering the saturated fat of milk and dairy products

Lactating cow diets were supplemented with high oleic acid sunflower oil over two production periods spanning two years, to modify the milk fat, partially replacing saturated fatty acids (SFA) with cis-monounsaturated fatty acids (MUFA). The resulting milk was used for ultra-high temperature (UHT) milk, butter and Cheddar cheese production, and fatty acid profiles were compared with those of conventionally-produced products. Fat from products made with modified milk had lower SFA and higher cis- and trans-MUFA concentrations than that of conventional products. This was consistent over production periods, demonstrating that this food chain approach could be adopted on a wider scale

Food chain approach to lowering the saturated fat of milk and dairy products

Lactating cow diets were supplemented with high‐oleic acid sunflower oil over two production periods spanning two years, to modify the milk fat, partially replacing saturated fatty acids with cis‐monounsaturated fatty acids. The resulting milk was used for ultrahigh‐temperature milk, butter and Cheddar cheese production, and fatty acid profiles were compared with those of conventionally produced products. Fat from products made with modified milk had lower saturated fatty acids and higher cis‐ and trans‐monounsaturated fatty acid concentrations than that of conventional products. This was consistent over both production periods, demonstrating that this food chain approach could be adopted on a wider scale

Impact of dairy fat manipulation on endothelial function and lipid regulation in human aortic endothelial cells exposed to human plasma samples: an in vitro investigation from the RESET study

Purpose Longer-term intake of fatty acid (FA)-modified dairy products (SFA-reduced, MUFA-enriched) was reported to attenuate postprandial endothelial function in humans, relative to conventional (control) dairy. Thus, we performed an in vitro study in human aortic endothelial cells (HAEC) to investigate mechanisms underlying the effects observed in vivo. Methods This sub-study was conducted within the framework of the RESET study, a 12-week randomised controlled crossover trial with FA-modified and control dairy diets. HAEC were incubated for 24 h with post-intervention plasma samples from eleven adults (age: 57.5±6.0 years; BMI: 25.7±2.7 kg/m2 ) at moderate cardiovascular disease risk following representative sequential mixed meals. Markers of endothelial function and lipid regulation were assessed. Results Relative to control, HAEC incubation with plasma following the FA-modified treatment increased postprandial NOx production (P-interaction=0.019), yet up-regulated relative E-selectin mRNA gene expression (P-interaction=0.011). There was no impact on other genes measured. Conclusion Incubation of HAEC with human plasma collected after longer-term dairy fat manipulation had a beneficial impact on postprandial NOx production. Further ex vivo research is needed to understand the impact of partial replacement of SFA with unsaturated fatty acids in dairy foods on pathways involved in endothelial function

Impact of heat treatment and acid gelation on polyphenol enriched milk samples

The effects of heat treatment and the stage of polyphenol addition to milk before or after heat treatment on the total phenolic content (TPC), ferric-ion reducing antioxidant power (FRAP), pH, casein micelle size (CMS) and whey protein denaturation content of milk-polyphenol mixtures were investigated. Four sources of phenolic compounds (green tea, white grape, tannic acid, gallic acid) were incorporated into pasteurized-skim milk. A heat treatment (85 °C for 30 min) was applied to pasteurized-skim milk either before (MhP) or after polyphenols addition (MhPh). Acid milk gels were produced using MhPh samples, and their TPC and FRAP were determined. Heat treatment decreased the TPC and FRAP values of the samples, except for tannic acid, probably due to increased polyphenol-protein interactions. However, MhPh tannic acid sample resulted in significantly higher FRAP value than MhP. The addition of gallic acid before heat treatment (MhPh) significantly increased CMS due to the lower pH of this sample during heating. Acid gelation decreased the extractable polyphenols, however there was no significant different on FRAP between acid gel and MhPh milk samples. This study showed that the properties of phenolic source, particularly pH, and the stage of polyphenol addition to milk had an impact on selected properties

Postprandial fatty acid profile, but not cardiometabolic risk markers, is modulated by dairy fat manipulation in adults with moderate cardiovascular disease risk: the randomized controlled REplacement of SaturatEd fat in dairy on Total cholesterol (RESET) study

Background: Chronic consumption of dairy products with a saturated fatty acid (SFA)-reduced, monounsaturated fatty acid (MUFA)-enriched content was shown to impact favourably on brachial artery flow-mediated dilatation (FMD). However, their acute effect on postprandial cardiometabolic risk biomarkers requires investigation. Objective: The effects of sequential high-fat mixed meals rich in fatty acid (FA)-modified or conventional (control) dairy products on postprandial FMD (primary outcome) and systemic cardiometabolic biomarkers in adults with moderate cardiovascular risk (≥50% above population mean) were compared. Methods: In a randomized cross-over trial, fifty-two participants (mean ± SEM age 53 ± 2 y; BMI 25.9 ± 0.5 kg/m2) consumed high-dairy fat breakfast (0 min; ~50 g total fat: Modified: 25 g SFAs, 20 g MUFAs; Control: 32 g SFAs, 12 g MUFAs) and lunch (330 min; ~30 g total fat; Modified: 15 g SFAs, 12 g MUFAs; Control: 19 g SFAs, 7 g MUFAs). Blood samples were obtained before and until 480 min after breakfast, with FMD assessed at 0, 180, 300 and 420 min. Data were analysed by linear mixed models. Results: Postprandial changes in cardiometabolic biomarkers were comparable between the different dairy meals, with the exception of a tendency for a 4% higher area under the curve (AUC) for the %FMD response following the modified dairy fat meals (P = 0.075). Plasma total lipid FA analysis revealed that incremental AUC responses were 53% lower for total SFAs, 214% and 258% higher for total cis-MUFAs (predominantly cis-9 18:1), and trans-18:1 respectively following the modified, relative to control dairy meals (all P < 0.0001). Conclusions: In adults at moderate cardiovascular risk, acute consumption of sequential high-fat meals containing FA-modified dairy products had little impact on postprandial endothelial function or systemic cardiometabolic biomarkers, but a differential effect on the plasma total lipid FA profile, relative to conventional dairy fat meals

Consumer acceptance of dairy products with a saturated fatty acid-reduced, monounsaturated fatty acid-enriched content

Agriculture-based reformulation initiatives, including oleic acid-rich lipid supplementation of the dairy cow diet, provide a novel means for reducing intake of saturated fatty acids (SFA) at a population level. In a blinded manner, this study evaluated the consumer acceptance of SFA-reduced, monounsaturated fatty acid-enriched (modified) milk, Cheddar cheese, and butter when compared with control and commercially available comparative samples. The effect of providing nutritional information about the modified cheese was also evaluated. Consumers (n = 115) rated samples for overall liking (appearance, flavor, and texture) using 9-point hedonic scales. Although no significant differences were found between the milk samples, the modified cheese was liked significantly less than a regular-fat commercial alternative for overall liking and liking of specific modalities and had a lower liking of texture score compared with the control cheese. The provision of health information significantly increased the overall liking of the modified cheese compared with tasting the same sample in a blinded manner. Significant differences were evident between the butter samples for overall liking and modalities of liking; all of the samples were significantly more liked than the commercial butter and sunflower oil spread. In conclusion, this study illustrated that consumer acceptance of SFA-reduced, monounsaturated fatty acid-enriched dairy products was dependent on product type. Future research should consider how optimization of the textural properties of fatty acid-modified (and fat-reduced) cheese might enhance consumer acceptance of this product