Fernanda Machado

Dairy cream, a common ingredient in various dishes and food products, is susceptible to rapid microbial growth due to its high water activity (≈0.97) and pH (≈6.7). Thus, it requires proper processing conditions to ensure food safety and extend shelf life. High-pressure processing (HPP) has emerged as a nonthermal food pasteurization method, offering an alternative to conventional heat-based techniques to obtain tastier, fresh-like, and safe dairy products without undesirable heat-induced alterations. This study assessed the impact of HPP (450 and 600 MPa for 5 and 15 min at 7 °C) and thermal pasteurization (75 °C for 15 s) on the microbiological and physicochemical attributes of dairy cream immediately after processing and throughout refrigerated storage (4 °C). HPP-treated samples remained microbiologically acceptable even on the 51st day of storage, unlike thermally pasteurized samples. Moreover, HPP decreased inoculated Escherichia coli and Listeria innocua counts by more than 6 log units to undetectable levels (1.00 log CFU/mL). pH, color (maximum variation of ΔE* up to 8.43), and fatty acid profiles remained relatively stable under varying processing conditions and during storage. However, viscosity exhibited higher values for HPP-treated samples (0.028 ± 0.003 Pa·s) compared to thermally processed ones (0.016 ± 0.002 Pa·s) by the 28th day of storage. Furthermore, volatile compounds (VOCs) of all treated samples presented a tendency to increase throughout storage, particularly acids and aliphatic hydrocarbons. These findings show HPP’s potential to significantly extend the shelf life of highly perishable dairy cream by at least 15 days compared to thermal pasteurization.

Worldwide, noncommunicable diseases accounted for 7 out of 10 deaths in 2019 (WHO), being ischemic heart disease one of the major contributors. Coffee has been implicated with several health benefits, namely the hypocholesterolemic potential, attributed to its high molecular weight compounds (e.g., polysaccharides and melanoidins) ability to affect cholesterol bioaccessibility. However, the pathways through which the nitrogen-containing brown-colored melanoidins (prevalent in many thermally processed foods) can affect cholesterol metabolism are partially unknown. In order to access coffee melanoidin’s cardioprotective potential, its colonic fermentability was simulated in vitro using human feces, employing simgi® (Dynamic Gastrointestinal Simulator). The fermentation degree was evaluated by the analysis of total carbohydrates and ammonium. The cardioprotective effect of the ferments was estimated by measuring short-chain fatty acids (SCFA) and primary and secondary bile salts (BS) after 48h of fermentation. Melanoidin total sugar content decreased due to polysaccharides fermentation, used as the primary source of energy, while ammonium production increased, owing to the degradation of the melanoidin’s proteins. SCFA production increased, as well as secondary BS, due to the microbiota activity. The conversion of primary to secondary BS (more hydrophobic) was significantly lower in the presence of melanoidins than in its absence (control). This decrease promoted by melanoidins may lower BS enterohepatic circulation, which in turn can lower cholesterol bioaccessibility and bioavailability, configuring a hypocholesterolemic effect. The in vitro colonic fermentation of coffee melanoidins, using human microbiota, yielded cardioprotective metabolites (SCFA) and decreased secondary BS, suggesting that they may regulate cholesterol homeostasis.

Several classes of polysaccharides have been described to have hypocholesterolemic potential, namely cholesterol bioaccessibility and bioavailability. This review will highlight the main mechanisms by which polysaccharides are known to affect cholesterol homeostasis at the intestine, namely the effect (i) of polysaccharide viscosity and its influence on cholesterol bioaccessibility; (ii) on bile salt sequestration and its dependence on the structural diversity of polysaccharides; (iii) of bio-transformations of polysaccharides and bile salts by the gut microbiota. Different quantitative structure–hypocholesterolemic activity relationships have been explored depending on the mechanism involved, and these were based on polysaccharide physicochemical properties, such as sugar composition and ramification degree, linkage type, size/molecular weight, and charge. The information gathered will support the rationalization of polysaccharides’ effect on cholesterol homeostasis and highlight predictive rules towards the development of customized hypocholesterolemic functional food.

(1) Background: Cholesterol bioaccessibility is an indicator of cholesterol that is available for absorption and therefore can be a measure of hypocholesterolemic potential. In this work, the effect of commercial espresso coffee and coffee extracts on cholesterol solubility are studied in an in vitro model composed by glycodeoxycholic bile salt, as a measure of its bioaccessibility. (2) Methods: Polysaccharide extracts from coffees obtained with different extraction conditions were purified by selective precipitation with ethanol, and their sugars content were characterized by GC-FID. Hexane extraction allowed us to obtain the coffee lipids. Espresso coffee samples and extracts were tested regarding their concentration dependence on the solubility of labeled ¹³C-4 cholesterol by bile salt micelles, using quantitative ¹³C NMR. (3) Results and Discussion: Espresso coffee and coffee extracts were rich in polysaccharides, mainly arabinogalactans and galactomannans. These polysaccharides decrease cholesterol solubility and, simultaneously, the bile salts’ concentration. Coffee lipid extracts were also found to decrease cholesterol solubility, although not affecting bile salt concentration. (4) Conclusions: Coffee soluble fiber, composed by the arabinogalactans and galactomannans, showed to sequester bile salts from the solution, leading to a decrease in cholesterol bioaccessibility. Coffee lipids also decrease cholesterol bioaccessibility, although the mechanism of action identified is the co-solubilization in the bile salt micelles. The effect of both polysaccharides and lipids showed to be additive, representing the overall effect observed in a typical espresso coffee. The effect of polysaccharides and lipids on cholesterol bioaccessibility should be accounted on the formulation of hypocholesterolemic food ingredients.