Sustainability Opportunities of Mediterranean Food Products through New Formulations Based on Carob Flour (Ceratonia siliqua L.)

Carob flour is increasingly popular in innovative functional foods. Its main producers are Mediterranean countries, facing health and nutrition challenges, and difficulties in tackling climate change. This study aims at formulating innovative sustainable bakery products of high nutritional value while pleasing the consumer and addressing regional challenges. Hence, carob flour was obtained by grinding sun-dried carob pods, thus reducing the environmental impact, and preserving carob’s high nutraceutical value. Different bread formulations resulted from the blend of wheat flour with carob pulp (5, 10, 20, and 30%) and/or seed powder (5 and 10%), with no added fats, additives, or processing aids. New products were evaluated for their textural, chromatic, nutritional, aromatic, and hedonic properties. Carob is rich in aroma, antioxidants, and prebiotic fibers, and does not contain gluten, so when combined with wheat, the proportion of gluten in bread is reduced. Carob is also rich in minerals (4.16% and 2.00% ash, respectively in seed and pulp), and breadmaking seems to generate lesser furane derivatives than in white bread. In short, carob is typically Mediterranean and is a valuable local resource in the formulation of sustainable foods with high nutritional value, low carbon footprint, safe, healthy, tasty, and affordable, all at once.

Concentrated Raw Fibers Enhance the Fiber-Degrading Capacity of a Synthetic Human Gut Microbiome

The consumption of prebiotic fibers to modulate the human gut microbiome is a promising strategy to positively impact health. Nevertheless, given the compositional complexity of the microbiome and its inter-individual variances, generalized recommendations on the source or amount of fiber supplements remain vague. This problem is further compounded by availability of tractable in vitro and in vivo models to validate certain fibers. We employed a gnotobiotic mouse model containing a 14-member synthetic human gut microbiome (SM) in vivo, characterized a priori for their ability to metabolize a collection of fibers in vitro. This SM contains 14 different strains belonging to five distinct phyla. Since soluble purified fibers have been a common subject of studies, we specifically investigated the effects of dietary concentrated raw fibers (CRFs)—containing fibers from pea, oat, psyllium, wheat and apple—on the compositional and functional alterations in the SM. We demonstrate that, compared to a fiber-free diet, CRF supplementation increased the abundance of fiber-degraders, namely Eubacterium rectale, Roseburia intestinalis and Bacteroides ovatus and decreased the abundance of the mucin-degrader Akkermansia muciniphila. These results were corroborated by a general increase of bacterial fiber-degrading α-glucosidase enzyme activity. Overall, our results highlight the ability of CRFs to enhance the microbial fiber-degrading capacity.

Concentrated Raw Fibers Enhance the Fiber-Degrading Capacity of a Synthetic Human Gut Microbiome

Consumption of prebiotic fibers to modulate the human gut microbiome is a promising strategy to positively impact health. Nevertheless, given the compositional complexity of the microbiome and its inter-individual variances, generalized recommendations on the source or amount of fiber supplements remain vague. This problem is further compounded by availability of tractable in vitro and in vivo models to validate certain fibers. We employed a gnotobiotic mouse model containing an a priori characterized 14-member synthetic human gut microbiome (SM) for their ability to metabolize a suit of fibers in vitro; the SM contains 14 different strains belonging to five distinct phyla. Since soluble purified fibers have been a common subject of studies, we specifically investigated the effects of concentrated raw fibers (CRFs)—containing fibers from pea, oat, psyllium, wheat and apple—on the compositional and functional alterations in the SM. We demonstrate that, compared to a fiber-free diet, CRF supplementation increased the abundance of fiber-degraders namely Eubacterium rectale, Roseburia intestinalis and Bacteroides ovatus and decreased the abundance of the mucin-degrader Akkermansia muciniphila. These results were corroborated by a general increase of bacterial fiber-degrading α-glucosidase enzyme activity. Overall, our results highlight the ability of CRFs to enhance the microbial fiber-degrading capacity.

Polylactose Exhibits Prebiotic Activity and Reduces Adiposity and Nonalcoholic Fatty Liver Disease in Rats Fed a High-Fat Diet

ABSTRACT Background Prebiotic dietary fibers change the intestinal microbiome favorably and provide a health benefit to the host. Objectives Polylactose is a novel fiber, synthesized by extrusion of lactose. We evaluated its prebiotic activity by determining its fermentability, effect on the microbiota, and effects on adiposity and liver lipids in a diet-induced obesity animal model. Methods Male Wistar rats (4–5 wk old) were fed normal-fat (NF, 25% fat energy) or high-fat (HF, 51% fat energy) diets containing different fibers (6% fiber of interest and 3% cellulose, by weight), including cellulose (NFC and HFC, negative and positive controls, respectively), polylactose (HFPL), lactose matched to residual lactose in the HFPL diet, and 2 established prebiotic fibers: polydextrose (HFPD) and fructooligosaccharide (HFFOS). After 10 wk of feeding, organs were harvested and cecal contents collected. Results HFPL animals had greater cecum weight (3 times greater than HFC) and lower cecal pH (∼1 pH unit lower than HFC) than all other groups, suggesting that polylactose is more fermentable than other prebiotic fibers (HFPD, HFFOS; P < 0.05). HFPL animals also had increased taxonomic abundance of the probiotic species Bifidobacterium in the cecum relative to all other groups (P < 0.05). Epididymal fat pad weight was significantly decreased in the HFPL group (29% decrease compared with HFC) compared with all other HF groups (P < 0.05) and did not differ from the NFC group. Liver lipids and cholesterol were reduced in HFPL animals when compared with HFC animals (P < 0.05). Conclusions Polylactose is a fermentable fiber that elicits a beneficial change in the gut microbiota as well as reducing adiposity in rats fed HF diets. These effects of polylactose were greater than those of 2 established prebiotics, fructooligosaccharide and polydextrose, suggesting that polylactose is a potent prebiotic.

Comparison of the effects of soluble corn fiber and fructooligosaccharides on metabolism, inflammation, and gut microbiome of high-fat diet-fed mice

Dietary fibers are essential components of a balanced diet and have beneficial effects on metabolic functions. To gain insight into their impact on host physiology and gut microbiota, we performed a direct comparison of two specific prebiotic fibers in mice. During an 8-wk follow up, mice fed a high-fat diet (HFD) were compared with mice on a normal diet (basal condition, controls) and to mice fed the HFD but treated with one of the following prebiotics: fructooligosaccharides (FOS) or soluble corn fiber (SCF). Both prebiotic fibers led to a similar reduction of body weight and fat mass, lower inflammation and improved metabolic parameters. However, these health benefits were the result of different actions of the fibers, as SCF impacted energy excretion, whereas FOS did not. Interestingly, both fibers had very distinct gut microbial signatures with different short-chain fatty acid profiles, indicating that they do not favor the growth of the same bacterial communities. Although the prebiotic potential of different fibers may seem physiologically equivalent, our data show that the underlying mechanisms of action are different, and this by targeting different gut microbes. Altogether, our data provide evidence that beneficial health effects of specific dietary fibers must be documented to be considered a prebiotic and that studies devoted to understanding how structures relate to specific microbiota modulation and metabolic effects are warranted.

Polylactose, a Novel Prebiotic Dietary Fiber, Reduces Adiposity and Hepatic Lipid Accumulation (P20-027-19)

Objectives Polylactose is a novel dietary fiber, synthesized by extrusion of lactose. To evaluate its potential as a prebiotic, we determined its fermentability, effect on the microbiome, and its effects on adiposity, fatty liver, and liver cholesterol in a diet-induced obesity animal model. Methods 72 male Wistar rats were fed normal fat (NF) or high fat (HF, 51% fat by kcal) diets containing various fibers (6% fiber of interest and 3% cellulose, by weight); including cellulose (NFC and HFC), polylactose (HFPL), matched lactose (HFML), matched to the residual lactose in the HFPL diet, and two established prebiotic fibers, polydextrose (HFPD) and fructooligosaccharides (HFFOS). After 10 weeks on experimental diets, organs were harvested and cecal contents collected for analysis. Results There were no significant differences in final body weights among the groups, nor did average daily food intake differ significantly among the HF-fed groups. HFPL animals had greater cecal weight (empty) and lower cecal contents pH when compared to all other groups, suggesting that polylactose is much more vigorously fermented than the other prebiotic fibers. This was also indicated by an increase in taxonomical abundance of probiotic species in the cecum. Epididymal fat pad weight was significantly decreased in the HFPL animals compared to all other HF groups (P < 0.05) and did not differ from the normal fat control (NFC). Liver lipids and cholesterol were significantly reduced in HFPL fed animals when compared to HFC fed animals and were numerically lower than all other HF groups. Transcriptome analysis of the liver revealed increased lipid oxidation and decrease lipid synthesis pathway expression, providing insights into mechanisms of reduction of lipid accumulation in the liver. Conclusions Polylactose is a vigorously fermentable fiber and elicits a beneficial change in the gut microbiome. We also demonstrate that consuming polylactose, in the context of a high fat diet, prevents the accumulation of body fat normally seen with this diet, as well as reduced lipid and cholesterol accumulation in the liver. As these effects of polylactose were greater than those of two established prebiotics, fructooligosaccharides and polydextrose, this suggests that polylactose is a potent prebiotic. Funding Sources Midwest Dairy Association.