Entomophagy is a long-time practice and a food source for many cultures. Still, many societies have abandoned it a long time ago, and regard it as a primal behavior. However, nowadays, the challenge for food demand, with the urge of new nutritional sources, and the problems of undernourishment, mainly on underdeveloped countries, has reached a point where a new perspective is demanded. This review gathers some of the most recent studies regarding the potential benefits and concerns of entomophagy, trying to show the potential of insects as food source and possible ways to introduce them in cultures that have disregarded entomophagy. Entomophagy is taking its place, showing the grand potential of insects as feed and food source. As neophobia and disgust are the main western cultures barriers to accept entomophagy, today’s comprehension of this practice and processing capabilities can take that source, to any dish in any form. A simple but nutritive insect powder can create a path to a widely, sustainable, rich food source—insects.

Dietary changes have accompanied the evolution of humanity and is proven to be fundamental in human evolution and well-being. Nutrition is essential for survival and as a matter of health and equilibrium of the human body. About 1/3 of the human diet is composed by fermented foods and beverages, which are widely distributed and consumed in different societies around the world, no matter the culture and lifestyle. Fermented foods are derived from the fermentation process of different substrates by microorganisms, and more importantly to humans, by those with beneficial characteristics, due to the positive impact on health. Food is transformed in the gut, gaining new proprieties, and increasing its value to the organism. The effects of fermented foods and beverages can be assessed by its influence at the gut microbiota level. Recent studies show the major importance of the gut microbiota role in modulating the organism homeostasis and homeorhesis. More crosslinks between health, gut microbiota and diet are being established especially in the gut–brain axis field. Therefore, the benefits of diet, in particularly of fermented foods and beverages, should be studied and pursued in order to promote a good health status.

The use of fecal inoculums for in vitro fermentation models requires a viable gut microbiota, capable of fermenting the unabsorbed nutrients. Fresh samples from human donors are used; however, the availability of fresh fecal inoculum and its inherent variability is often a problem. This study aimed to optimize a method of preserving pooled human fecal samples for in vitro fermentation studies. Different conditions and times of storage at −20 °C were tested. In vitro fermentation experiments were carried out for both fresh and frozen inoculums, and the metabolic profile compared. In comparison with the fresh, the inoculum frozen in a PBS and 30% glycerol solution, had a significantly lower (p < 0.05) bacterial count (<1 log CFU/mL). However, no significant differences (p < 0.05) were found between the metabolic profiles after 48 h. Hence, a PBS and 30% glycerol solution can be used to maintain the gut microbiota viability during storage at −20 °C for at least 3 months, without interfering with the normal course of colonic fermentation.

Recently, the bioactive potential of several functional ingredients and biomolecules has been evaluated regarding human and animal nutrition. The digestive process from food intake to absorption and metabolism are important events that induce changes in ingredients, which affect their bioactivity. Consequently, there is a need to assess the bioavailability and bioaccessibility of these compounds. The methodology for the simulation of the human gastrointestinal tract has been standardized (INFOGEST protocol), while a gastrointestinal protocol for other animals (e.g., ruminants or broilers) has yet to be established. However, INFOGEST allows us only to predict bioaccessibility, leaving a gap regarding a methodology able to assess bioavailability by mimicking intestinal permeability and absorption. Several approaches—including in vitro, ex vivo, in situ and in vivo methods—can be found in the literature, aiming to tackle transepithelial routes, but leading to different results concerning the bioefficiency of the compounds studied. Therefore, this review aims to assess the current state-of-the-art regarding monogastric intestinal dynamics, absorption, and permeability events. Moreover, it compiled methodologies for simulating intestinal absorption in several biological systems, while reasoning their advantages, disadvantages, applications in ingredient development and the existing gaps.

The Tenebrio molitor insect flour (TMIF) is considered a nutritive food ingredient, but its impact at the gut microbiota level and its potential prebiotic activity still need be assessed. For such studies, an in vitro simulation model of gut microbiota was optimized. Pure cultures of Lactobacillus and Bifidobacterium strains in monocultures and co-cultures (pairs and consortium) were used in this model to evaluate the effect of TMIF on the viability and metabolic activity of those bacteria. The optimization of the in vitro model of the gut microbiota was successful, and growth of the most important groups of bacteria in the gut microbiota was observed. So this model can be used to study the effects of other ingredients at that level. It also enabled pinpointing the prebiotic effects of the studied TMIF suggesting possible symbiotic interactions. In addition, the direct effect of the TMIF on bacterial cells, when in nutritive stress was also evaluated. In terms of TMIF effects on probiotic bacteria viability and growth, no negative effects were observed, and even an enhancement of growth and an increase of production of short chain fatty acids (SCFA) and lactate, in most of the cases, was observed. Also, this study showed that TMIF helps in maintaining the viability of bacteria during incubation time when these are under nutritional stress conditions. A potential prebiotic effect of TMIF is then predictable with this study, opening a path to new research on this subject.