Impact of elderly gastrointestinal alterations on in vitro digestion of salmon, sardine, sea bass and hake: Proteolysis, lipolysis and bioaccessibility of calcium and vitamins

A Review on In Vitro Evaluation of Chemical and Physical Digestion for Controlling Gastric Digestion of Food

Food digestion in the gastrointestinal is a series of processes consisting of chemical and physical digestion. Recently, developing foods with controlled digestion in the stomach may attract more attention. Hydrogel foods are useful tools for designing foods with controlled digestion because it is relatively easy to design their food characteristics by adjusting the type and content of the additives. This review introduces the latest status of in vitro gastric digestion as a food characterization system. The in vitro evaluation of chemical gastric digestion by gastric acid and digestive enzymes focuses on INFOGEST-standardized gastrointestinal digestion protocols for healthy adults, infants, and older adults. For the in vitro evaluation of physical gastric digestion by peristalsis, the current development of gastrointestinal tract devices that precisely or efficiently simulate the shape of the stomach and gastric peristalsis is described. In addition, we introduce studies that have utilized these devices to investigate the gastric digestion behavior of hydrocolloid foods with different mechanical characteristics.

The Effects of a Microbial Enzyme Mixture on Macronutrient Hydrolysis in a Static Simulation of Oro-Gastric Digestion That Models Human Digestive Senescence

Observational studies have shown that human digestive function declines naturally with age. Oral enzyme supplementation is a candidate strategy to enhance macronutrient digestion in older adults. The objective of this study was to test the effects of a mixture of six microbial enzyme preparations (ENZ) on nutrient bioaccessibility from a mixed meal in an in vitro model of digestive senescence. The mixed meal included chicken meat, peas, and potatoes. The INFOGEST 2.0 static simulation of oro-gastric digestion was used to model human digestive physiology along with a consensus protocol to model aging. Analytical testing of gastric digesta included measurements of free amino nitrogen (FAN), amino acid (AA), fatty acid (FA), glycerol, maltose, and glucose concentrations. Peptide distribution profiles were evaluated by size exclusion chromatography (SEC) and gel electrophoresis. After simulating digestion of the mixed meal, all nutrient bioaccessibility outcomes compared to pepsin-only controls, except glycerol, were further enhanced by ENZ in the aging condition compared to the standard condition (FAN: 77.1 vs. 39.3%; essential AA: 100.4 vs. 57.6%; total FA: 12.8- vs. 8.0-fold; maltose: 142.1 vs. 0.7%). SEC confirmed ENZ's proteolytic capacity to generate more lower molecular weight peptides and free AAs in standard and aging conditions compared to pepsin alone. Gel electrophoresis confirmed proteolytic enhancement with ENZ. These data showcase ENZ's hydrolytic activity toward macronutrients and suggest ENZ's capacity to compensate for reduced pepsin activity in an aging-adapted oro-gastric digestion simulation.

Determination of collagen types and mineral contents in fish skin and collagen-containing skin-derived protein hydrolysates before and after in vitro simulated digestion

An in vitro digestion model was established to characterize the types of collagens in skin of cod, white fish, and salmon as well as their collagen-containing skin-derived protein hydrolysates (CSPH) before and after digestion. Moreover, the mineral content and their bioaccessibility were evaluated. Finally, the presence of heavy metals was evaluated to assess the safety of these products. The results showed that white fish protein exhibited a high digestibility, reaching up to 92%. Among the collagen products, salmon collagen had the highest digestibility (∼73%). Protein identification revealed that the emPAI of type I collagen in digested skin and CSPH was higher than that of undigested samples. In addition, raw skins had higher contents of P, K, Ca and Mg, and the mineral content of CSPH was lower than that of unprocessed skins. Among the minerals studied, Ca and Cu showed the highest bioaccessibility in raw skin cod, being 32% and 26%, respectively. The bioaccessibility of Cu in raw skin salmon was also higher (∼34%). Moreover, in CSPH, Mg, K and Cu can be easily digested and absorbed. Regarding heavy metals, As and Pb were below the respective safe limits in all raw skins and CSPH, while Hg and Cd were not detected in the fish CSPH. Fish-derived collagen has gained significant attention due to its numerous health benefits, high bioavailability, and superior sustainability compared to animal collagen. Moreover, different types of collagens offer distance roles and advantages in the body. However, there are limited reports on how collagen structure and type may change during the digestive process. This study seeks to deepen our understanding of the economic value of fish collagen, as well as the mechanisms of its absorption and digestion. By investigating processes, the research aims to provide a clearer insight into the physiological effects of fish-derived collagen, which can inform the development of tailored collagen supplementation programs based on specific health needs.

Microbial protease supplementation improves gastric emptying and protein digestive fate of beef for the elderly under dynamic in vitro digestion

Elderly individuals experience age-related declines in digestive function, which can hinder the digestion of dietary proteins and thereby negatively impact overall health. This study provides a comprehensive understanding of the protein digestive fate of beef with Protease-DS supplementation by analyzing gastric emptying behavior and amino acid and peptide profiles during a simulated in vitro elderly digestion process. The adult model exhibited superior gastric emptying capacity, with relatively rapid and early expulsion of gastric digesta into the intestinal segment. Additionally, the underperforming elderly model showed notable improvement in the emptying process with Protease-DS supplementation, achieving a rate of 0.0110 min-1, which was close to the adult model of 0.0125 min-1 and significantly faster than the elderly model of 0.0080 min-1. Protein digestibility in the elderly model was significantly enhanced with Protease-DS supplementation, increasing from 55.62 % to 63.60 %, approaching that of the adult model (69.60 %). Protease-DS significantly improved the essential amino acid score (EAAS), particularly for methionine + cysteine, phenylalanine + tyrosine, lysine, and leucine. Furthermore, it enhanced the release of unique polypeptide fragments, distinct from those in both the adult and elderly models, and demonstrated significant anti-amnesic and antithrombotic bioactive functions, highlighting its potential to improve memory and reduce blood clotting. This study provides guidance for elderly consumers on enhancing dietary protein digestion through protease supplementation, presenting it as an effective strategy to address protein deficiency and improve health and well-being.

Comparison of in vitro digestive characteristics of proteins from different sources in simulated elderly gastrointestinal conditions

This study aimed to evaluate the impact of in vitro digestive characteristics of five different protein sources (fish, crab, beef, chicken, and soy) in adults and elderly individuals. Simulated gastrointestinal tract degradation in the elderly significantly reduced the digestibility of all proteins. The Elderly model had difficulties digesting any protein that had a firm structure or was prone to aggregation. Of the five protein types, soy protein was the least easily digested. Ultraviolet spectroscopy and SDS-PAGE analysis revealed that beef and crab proteins contain myoglobin and hemocyanin, respectively, making their structure firm. Simultaneously, alkali-soluble proteins in meat were more likely to be digested by the elderly than salt-soluble proteins. The alkali-soluble protein percentage in fish protein was the highest, including the best in vitro digestion characteristics in the elderly population. This study provides novel and significant recommendations for the elderly's daily intake of various protein sources.

Characterization, in vitro elderly digestion, and organoids cell uptake of curcumin-loaded nanoparticles

Curcumin, a bioactive compound, showed versatile in anti-inflammatory and anti-cancer ability, while their biological fate in elderly is unclear. In this study, curcumin-loaded nanoparticles based on octyl succinate hydrate (OSA) starch and sodium caseinate were prepared and the in vitro elderly digestion and absorption fate was investigated. The loading capacity of curcumin-loaded nanoparticles prepared from OSA starch (HI), sodium caseinate (SC) and OSA starch‑sodium caseinate (HS) were all higher than 15%. Curcumin release behavior of the three nanoparticles during in vitro digestion conformed to first-order kinetics. Meanwhile, the transport efficiency of curcumin for HI, SC, and HS increased significantly than the free curcumin (near 1-fold), and the permeability were 1.9, 2.0, and 2.0 times, respectively. The gene expressions of TNF-α, SREBP2 and NPC1L1 in the organoids were enhanced than control group. This study provided scientific reference and guidance for encapsulation of curcumin and digestion and absorption properties in elderly.

Effect of high pressure homogenization on in vitro digestibility and colon fermentability of pea protein-rich bread designed for elderly consumers

Enrichment of staple foods with proteins can be a solution to tackle protein-energy malnutrition in the elderly. For instance, bread can be enriched with pea proteins that are cheap, sustainable and easily digestible. Non-conventional technologies, such as high pressure homogenization (HPH), can improve the digestibility of plant proteins. To characterize the health functionality of pea-enriched bread, a functional bread tailored to elderly consumers was developed by substituting 5% wheat flour with untreated or HPH-treated pea protein concentrate. Protein digestibility and colon fermentability were assessed by mimicking elderly in vitro gastrointestinal and gut microbiota conditions and compared with adult conditions. Bread reformulation with pea proteins affected physical and chemical properties and produced an increase in hardness, which is one of the key features for the acceptability of bread by the elderly. The highest hardness value was observed for pea protein bread, followed by HPH-treated pea protein bread and wheat bread. In vitro protein digestibility and fermentability were affected by reformulation and by physiological digestive conditions, with lower digestibility under elderly conditions compared to adult ones. The obtained results may contribute to a better understanding of food digestibility under different gastrointestinal conditions and its dependence on physiological and formulation factors, and ultimately would help to design age-tailored foods.

Assessing food digestion in the elderly using in vitro gastrointestinal models

With the global population of individuals aged 65 and older projected to exceed 1.5 billion by 2050, understanding the impact of aging on digestion and nutrient absorption is essential for addressing the nutritional needs of the elderly. This review explores the limitations of traditional in vivo studies and underscores the growing importance of in vitro gastrointestinal models as an ethical and cost-effective alternative for investigating digestion in the elderly. The review provides a comprehensive analysis of age-related physiological changes in the gastrointestinal tract (GIT), and critically evaluates how static and dynamic in vitro models have been adapted to simulate these changes. We also discuss the significant challenges these models face in accurately replicating the complexities of elderly digestion, particularly in mimicking the interactions between digestive processes and the gut microbiome. By addressing these challenges, particularly through the development of more physiologically relevant and personalized in vitro models, this review highlights the potential to enhance our understanding of elderly digestion and improve nutritional strategies, ultimately contributing to better health outcomes for the aging population.

Impact of age on the digestion of cream cheese formulated with opposite caseins to whey proteins ratios: An in vitro study

Ageing leads to changes in the functionality of the digestive tract but the effect of age on digestion and absorption of nutrients remains unclear. The objective of this study was to investigate in vitro the digestion of two high-protein dairy products similar to cream cheese (24 % w/w proteins, 20 % w/w lipids) with opposite casein to whey protein ratios, 80:20 (WP-20), and 20:80 (WP-80). The new static digestion model adapted to the general older adult population (≥65 y.) proposed by INFOGEST was used, as well as the standard version of the protocol. Kinetics of proteolysis and lipolysis were compared between both models for each product, in the gastric and intestinal phases of digestion. In both cream cheeses, the degree of protein hydrolysis (DH-P) was significantly lower for older adults than for young adults at the end of the gastric phase (-19 % for WP-20, and -44 % for WP-80), and at the end of the intestinal phase (-16 % for WP-20, and -20 % for WP-80). The degree of lipid hydrolysis (DH-L) was also significantly lower for older adults than for young adults at the end of the digestion for WP-20 (-30 %), but interestingly it was not the case for WP-80 (similar DH-L were measured). Free fatty acids were also released faster from WP-80 than from WP-20 in both digestion conditions: after 5 min of intestinal digestion DH-L was already ≈32 % for WP-80 against 14 % for WP-20. This was attributed to the opposite casein to whey protein ratios, leading to the formation of different gel structures resulting in different patterns of deconstruction in the gastrointestinal tract. This study highlights the fact that it is essential to carefully consider the composition, structure, and digestibility of foods to develop products adapted to the specific needs of the older adult population.

Desserts Enriched with a Nanoemulsion Loaded with Vitamin D3 and Omega-3 Fatty Acids for Older People

The food industry is challenged to develop nutritious and palatable foods that satisfy older people's needs. So, this work aimed to study the incorporation of nanoemulsions enriched with vitamin D3 and omega-3 fatty acids into two desserts (yogurt and fruit puree), characterizing their nutritional profile, viscosity, and color properties and evaluating their in vitro bioaccessibility and sensory response. The results showed that adding nanoemulsion modified the nutrition profile of desserts due to increasing lipids and calories. The desserts' physical properties were also affected, with a decrease in viscosity and a lightening of color. Regarding digestion, the enriched desserts presented a low release of free fatty acids (14.8 and 11.4%, respectively). However, fruit puree showed the highest vitamin D3 and omega-3 fatty acid in vitro bioaccessibility (48.9 and 70.9%, respectively). In addition, older consumers found this dessert more acceptable than yogurt due to the adequate intensity of its sensory attributes (aroma, flavor, sweetness, and consistency). Therefore, the fruit puree can be enriched with nanoemulsions loaded with vitamin D3 and omega-3 fatty acids to improve the bioaccessibility of lipid bioactive compounds and sensory performance, offering a health-enhancing option for older consumers.

The digestion fates of lipids with different unsaturated levels in people with different age groups

The digestion behavior of lipids plays a crucial role in their nutritional bioaccessibility, which subsequently impacts human health. This study aims to investigate potential variations in lipid digestion profiles among individuals of different ages, considering the distinct physiological functions of the gastrointestinal tract in infants, aging populations, and healthy young adults. The digestion fates of high oleic peanut oil (HOPO), sunflower oil (SO), and linseed oil (LINO) were investigated using in vitro digestion models representing infants, adults, and elders. Comparatively, lipid digestion proved to be more comprehensive in adults, leading to free fatty acid (FFA) levels of 64.53%, 62.32%, and 57.90% for HOPO, SO, and LINO, respectively. Besides, infants demonstrated propensity to selectively release FFAs with shorter chain lengths and higher saturation levels during the digestion. In addition, in the gastric phase, particle sizes among the elderly were consistently larger than those observed in infants and adults, despite adults generating approximately 15% FFAs within the stomach. In summary, this study enhances our fundamental comprehension of how lipids with varying degrees of unsaturation undergo digestion in diverse age groups.

Utilizing the influence of protein enrichment of meal components as a strategy to possibly prevent undernutrition in the elderly: an in vitro approach

Nutritional strategies are required to limit the prevalence of denutrition in the elderly. With this in mind, fortified meals can provide more protein, but their digestibility must be ensured. Using a dynamic in vitro digester, DIDGI®, programmed with the digestion conditions of the elderly, we evaluated the supplementation of each component of a meal and assessed protein digestibility, amino acid profile, micro-nutrients and vitamins bioaccessibility for a full course meal. Higher protein digestibility was evidenced for the fortified meal, with higher release of essential amino acids. Moreover the large increase of leucine released was comparable to the range advocated for the elderly to favour protein anabolism. This in vitro study underlines the interest of using dish formulations to meet the nutritional needs of seniors, which is why this work will be completed by a clinical study in nursing home.

Effect of Fishing Season and Size on the Physicochemical and Microbiological Characteristics of Salted Sardines (Sardina pilchardus)

Salting is the preferred method used by manufacturers to preserve the quality of fish. The aim of this study was to investigate the effect of size and fishing season on the physicochemical and microbiological characteristics of sardines. Two batches of sardines, caught, in winter and summer, were sorted according to size, salted, matured, and stored at 18°C. A control batch, consisting of sardines from the summer batch, was also prepared without subcutaneous fat. Various physicochemical and microbiological parameters were monitored during 12 weeks of maturation. The recorded values showed a decrease in pH, moisture content, and water activity (a measure of the water available for biological and chemical processes), while salt concentration increased. When comparing samples, the lowest values for histamine (94.3 and 48.3 mg/kg) and lipids (9.3 and 8.2%) were observed in the large and small sardines of the winter batch, respectively. In the summer batch, higher values were recorded for histamine (847.3 and 127.9 mg/kg) and lipids (14.5 and 8.6%) in the large and small sardines. Furthermore, the removal of fat in control of the summer batch resulted in lower histamine accumulation compared to the batch with fat. The microbiological parameters showed a decrease in the number of nonhalophile bacteria, while the number of halophile bacteria increased. This study showed a strong correlation between three important factors, fishing season, fish size, and histamine content, which can contribute to the successful salting of sardines and ensure the wholesomeness of the final product.

From static to semi-dynamic in vitro digestion conditions relevant for the older population: starch and protein digestion of cooked lentils

In the context of adequately feeding the rising older population, lentils have an important potential as sources of (plant-based) protein as well as slowly digestible bio-encapsulated starch and fibre. This study evaluated in vitro digestion of protein and starch in lentils under conditions representing the gastrointestinal tract of older adults. Both static and semi-dynamic simulations were applied to analyze the effect of specific gastrointestinal conditions (healthy versus older adult) on macronutrient digestion patterns. Gastric proteolysis was strongly dependent on applied gastric pH (gradient), leading to a lower extent of protein hydrolysis for simulations relevant for older adults. Fewer and smaller (lower degree of polymerization, DP) bioaccessible peptides were formed during gastric proteolysis under older adult compared to healthy adult conditions. These differences, developed during the in vitro gastric phase, were compensated during small intestinal digestion, yielding similar final proteolysis levels regardless of the applied simulation conditions. In contrast, in the presence of saliva, amylolysis was generally accelerated under older adult conditions. Moreover, the current work highlighted the importance of considering saliva (or salivary amylase) incorporation in simulations where the applied gastric pH (gradient) allows salivary amylase activity. Under both healthy and older adult conditions, in vitro starch hydrolysis bio-encapsulated in cotyledon cells of cooked lentils was attenuated, compared to a white bread reference.

Behaviour of texture-modified meats using proteolytic enzymes during gastrointestinal digestion simulating elderly alterations

This study aimed to apply different proteolytic enzymes (bromelain, papain, and flavourzyme) to develop texture-modified meats suitable for people with chewing or swallowing problems. The samples were categorised at level 6 (soft and bite-sized food) of the dysphagia diet, characterised in terms of physicochemical and textural parameters, and evaluated for their behaviour during gastrointestinal digestion simulating elderly alterations. In general, the enzyme-treated samples had lower moisture content, weight, and diameter of the piece of meat, and presented colour differences compared to the control samples. Textural analyses did not show significant differences in terms of hardness and cohesiveness for the texture-modified meats, while flavourzyme-treated samples presented less elasticity. Instrumental mastication assay showed the breakdown of samples' structure mainly during the first mastication cycles, with flavourzyme-treated samples presenting slightly higher consistency. The protein digestibility of the meats greatly increased after simulated gastrointestinal digestion, but a decrease in proteolysis for the control and papain-treated samples in the altered gastric model and an increase for flavourzyme-treated samples in the altered both gastric and intestinal model were shown compared to standard conditions. These results allow integrating knowledge to design foods that better meet the requirements of dysphagics or elderly people.

The impact of age-related digestive disorders on in vitro digestibility of macronutrients and bioaccessibility of minor components of chia seeds

Gastrointestinal (GI) functions deteriorate with age, primarily affecting protein digestion. The consumption of chia seeds may be helpful for the elderly because they offer a vegetable-based source of proteins, healthy lipids, fibre and micronutrients. The impact of common age-related GI deterioration on chia seed digestibility was assessed using in vitro digestion models. The goal was to study the potential of chia seeds as part of the diet of seniors. Deterioration in the oral, gastric and intestinal stages of digestion was cumulatively assessed in three digestion models: E1 (deterioration in oral conditions), E2 (deterioration in oral and gastric conditions) and E3 (deterioration in oral, gastric and intestinal conditions). Less efficient chewing (E1) decreased proteolysis, lipolysis and antioxidant capacity (p < 0.05). In contrast, deterioration in gastric functions seemed to affect only total polyphenolic content. Finally, in the model simulating the greatest deterioration in digestive functions (E3), all measured variables were negatively affected (proteolysis, lipolysis, amino acid release, total phenolic content, antioxidant capacity and calcium). Calcium bioaccessibility fell by 24 % with a decrease in pancreatic enzymes and bile secretion (E3). Age-related reduced digestive function did not affect the ratio of essential to non-essential amino acids in the digested samples in any case. However, under suboptimal GI conditions (E3), amino acids such as valine, leucine and isoleucine, which are important for sarcopenia prevention in the elderly, fell by 39 %, 49 % and 44 %, respectively. These findings might be helpful for further in vitro studies of chia seeds as a possible food ingredient. They may also be useful for the development of more targeted nutrition strategies in the elderly.

Adult and elderly in vitro digestibility patterns of proteins and carbohydrates as affected by different commercial bread types

Carbohydrate and protein digestibility were assessed in different commercial bread types, i.e., soft, durum, and whole wheat, by applying in vitro digestion protocols mimicking adult or elderly physiological conditions. Protein digestibility was measured after the gastric and intestinal phases by the o-phthalaldehyde spectrophotometric assay (OPA). Carbohydrate digestibility was assessed by determining the incremental area under glucose curve during the intestinal phase of digestion to estimate the glycaemic index (GI_e). Finally, the correlation between protein and carbohydrate digestibility was computed. Bread proteins presented a high gastric resistance, with a digestibility < 10% in all cases while after the intestinal phase, protein digestibility increased, ranging from 40 to 70%. Protein digestibility was affected both by formulation, with whole wheat bread presenting the lowest values, and by physiological conditions, with restrained digestibility under elderly conditions compared to adult ones. The GI_e decreased in the order durum > soft > whole, under both adult (119, 101, and 82, respectively) and elderly (107, 93, and 65, respectively) conditions. The extent of differences under different physiological settings varied depending on the bread type, without significant changes for soft wheat bread (ΔGI_e = 8), whereas elderly conditions significantly reduced GI_e both for durum (ΔGI_e = 12) and whole (ΔGI_e = 17) wheat bread. An almost strong positive correlation between protein digestibility and GI_e was observed (p = 0.69), indicating that concomitantly addressing sarcopenia and type 2 diabetes can only be pursued by a compromise solution or more desirably requires identifying technological strategies to maximize protein digestibility while restraining the glycaemic response.

Comparison of protein in vitro digestibility under adult and elderly conditions: The case study of wheat, pea, rice, and whey proteins

In this study an in vitro static digestion method mimicking the elderly gastrointestinal conditions was designed by adapting the physiological parameters described in the INFOGEST standardized static in vitro digestion protocol, i.e., pH, digestive phase duration, concentrations of enzymes and bile salts, to the aged GI transit. The digestibility of proteins from different sources (pea, rice, wheat, and milk whey) was then assessed. Protein digestive behaviour was monitored after gastric and intestinal phases by BCA assay and SDS-PAGE to assess protein hydrolysis both from a quantitative and a qualitative point of view. Digested samples were also analysed for physical characteristics in terms of particle size and zeta potential. Data acquired under elderly gastrointestinal conditions were compared to those obtained by using the INFOGEST protocol designed to study adult digestion. Results clearly showed that the elderly gastrointestinal conditions deeply affected proteolysis leading to a general reduction of protein digestibility in comparison to the adult model. The proteolysis extent depended on the protein source with whey and rice proteins showing about 20% reduction using the model mimicking the elderly gut, followed by pea (about 10% reduction) and wheat (about 4% reduction) proteins. The knowledge of protein digestibility under elderly gastrointestinal conditions generated in this study could be useful in the attempt to develop age-tailored products.

Effect of gastrointestinal alterations mimicking elderly conditions on in vitro digestion of meat and soy proteins

Among the physiological functions declining with aging, decreased secretion of gastric fluid, achlorhydria, is commonly observed. We evaluated the digestion of meat (chicken, beef, and pork) and soy proteins using in vitro conditions mimicking gastrointestinal (GI) digestion in adults (control, C) and elderly individuals with achlorhydria (EA). Changes in degrees of hydrolysis (DH), SDS-PAGE profiles, peptide concentrations, and proteomic profiles during digestion were investigated. Digestion under the EA conditions markedly decreased DH, especially for soy proteins. SDS-PAGE profiling and proteomics showed that myofibrillar/sarcoplasmic proteins from meat and glycinin/beta-conglycinin from soy were most affected by digestion conditions. Our results indicated that differences in the digestibility of meat protein between EA and control conditions gradually narrowed from the gastric to the intestinal phase for meat protein, while a pronounced difference persisted in the intestinal phase for soy protein. Our work provides new insight of value for future dietary recommendations for elderly individuals.

Designing food for the elderly: the critical impact of food structure

Ageing is an unavoidable progressive process causing many changes of the individual life. However, if faced in an efficient way, living longer in a healthy status could be an opportunity for all. In this context, food consumption and dietary patterns are pivotal factors in promoting active and healthy ageing. The development of food products tailored for the specific needs of the elderly might favour the fulfilment of nutritionally balanced diets, while reducing the consequences of malnutrition. To this aim, the application of a food structure design approach could be particularly profitable, being food structure responsible to the final functionalities of food products. In this narrative review, the physiological changes associated to food consumption occurring during ageing were firstly discussed. Then, the focus shifted to the possible role of food structure in delivering target functionalities, considering food acceptability, digestion of the nutrients, bioactive molecules and probiotic bacteria.

Evaluation of digestibility differences for apple polyphenolics using in vitro elderly and adult digestion models

We evaluated the in vitro digestibility of apple polyphenols mimicking elderly and adult digestion models (dynamic and static systems). The digestibility of total apple polyphenols in small intestine was much higher in the adult dynamic system (62 μg/100 g fresh apple) compared to the static system (20 μg/100 g fresh apple) and elderly dynamic digestion conditions (33 μg/100 g fresh apple). Elderly in vitro static digestion showed better antioxidant activity than the adult system (OH and ABTS⁺ methods). Thus, the in vitro dynamic digestion system can more truly reflect the digestion of apple polyphenols than static digestion system. Moreover, elderly digestion conditions negatively influenced the digestibility of apple polyphenols including chlorogenic acid, epicatechin, phlorizin, rutin, phloretin, hyperoside, proanthocyanidin B₂, and quercetin. Hence, appropriate selection of in vitro digestion models for elderly is a prerequisite to exploring the digestibility of phytochemicals for the development of functional food products for elderly.

Elderly gastrointestinal conditions increase sterol bioaccessibility in a plant sterol-enriched beverage: adaptation of the INFOGEST method

Elderly people suffer from a higher cardiovascular risk. Thus, the fortification of foods with plant sterols (PSs), which have a cholesterol-lowering function, could be of great interest for this target group. To date, no studies have analyzed how the gastrointestinal conditions of the elderly affect PS bioaccessibility. Therefore, this study evaluated the impact of the adaptation of the gastric phase alone and in combination with the intestinal phase on sterol bioaccessibility. For this purpose, the standardized INFOGEST 2.0 method previously adapted for sterol bioaccessibility evaluation in healthy adults was applied to PS-enriched milk-based fruit beverages, examining changes in enzyme activity, incubation time, agitation and pH, based on elderly physiology. The results suggest that the specific gastrointestinal conditions of the elderly could increase absorption of PSs, since their bioaccessibility (%) in a PS-enriched milk-based fruit beverage was significantly increased compared with that in adults (14.95 ± 0.33 vs. 7.96 ± 0.26), also indicating that these conditions increase the bioaccessibility of the beverage's own cholesterol (61.25 ± 2.91 vs. 20.86 ± 2.79). These data support the recommendation of foods of this type for the elderly who can benefit from the increase in bioaccessibility of PSs to have an improved potential cholesterol lowering effect, thus decreasing their risk of cardiovascular disease. However, the performance of subsequent in vivo tests to confirm these results is necessary.

Effect of the Mediterranean diet on gingivitis: A randomized controlled trial

AIM

This study aimed to investigate the effects of a 6-week Mediterranean diet (MD) intervention on gingival inflammatory and anthropometric parameters of patients with gingivitis.

MATERIALS AND METHODS

Forty-two participants were allocated to MD group (MDG) or control group (CG). After a 2-week equilibration period regarding dental care procedures, only MDG changed their diet to MD for 6 weeks, supported by a diet counselling. Gingival and anthropometric parameters were assessed at baseline (T0), Week 2 (T1, beginning of MD intervention), and Week 8 (T2). Adherence to MD was assessed by the Mediterranean Diet Adherence Screener (MEDAS); dietary behaviour was evaluated by the German Health Interview and Examination Survey for Adults Food Frequency Questionnaire (DEGS-FFQ).

RESULTS

Plaque values remained constant in both groups. Inflammatory periodontal and anthropometric parameters decreased in the MDG only (gingival index: T1 1.51 ± 0.21, T2 1.49 ± 0.24; bleeding on probing: T1 51.00 ± 14.65, T2 39.93 ± 13.74; body weight: T1 79.01 ± 15.62, T2 77.29 ± 17.00; waist circumference: T1 84.41 ± 10.1, T2 83.17 ± 10.47 (p < .05). MEDAS revealed a sufficient diet adherence for MDG.

CONCLUSION

Within this study, gingival inflammatory parameters were significantly reduced by MD, whereas plaque parameters remained constant. The diet counselling achieved sufficient adherence with beneficial changes in weight loss and waist circumference.

Understanding protein digestion in infants and the elderly: Current in vitro digestion models

The last decades have witnessed a surge of interest in the fate of dietary proteins during gastrointestinal (GI) digestion. Although several in vitro digestion models are available as alternatives to clinical experiments, most of them focus on the digestive conditions of healthy young adults. This study investigates the static/dynamic models used to simulate digestion in infants and the elderly and considers the related in vivo conditions. The in vitro digestive protocols targeting these two groups are summarized, and the challenges associated with the further development of in vitro digestion models are discussed. Static models rely on several factors (e.g., enzyme concentration, pH, reaction time, and rotation speed) to differentiate digestive conditions depending on age. Dynamic models can more accurately simulate the complex digestion process and allow the inclusion of further parameters (sequential secretion of digestive fluids, gradual changes in pH, peristaltic mixing, GI emptying, and the inoculation of luminal microbiota). In the case of infants, age or growth stage clarification and the differentiation of digestive protocols between full-term and preterm infants are required, whereas protocols dealing with various health statuses are required in the case of the elderly, as this group is prone to oral cavity and GI function deterioration.

Impact of Cooking Preparation on In Vitro Digestion of Eggs Simulating Some Gastrointestinal Alterations in Elders

This study aimed to in vitro assess the impact of the cooking process of eggs (hard-boiled, poached, and omelet) on nutrients digestibility and vitamins A and D3 bioaccessibility under elderly gastrointestinal (GI) conditions. Three elderly digestion models were mimicked: oral (E1); oral and gastric (E2); and oral, gastric, and intestinal (E3), and a healthy adult model (C). Proteolysis extent reduced after digestion of omelet under the E3 model (p < 0.05) (up to 37% of reduction). Thus, hard-boiled and poached were more recommendable to enhance protein digestibility in elders. Altered GI conditions negatively influence neither the absorbable lipid fraction nor the cholesterol stability. Finally, vitamin A bioaccessibility was not affected but D3 slightly decreased with the elderly (E3). Hence, the digestion of nutrients was dependent on the resulting matrix, poached being the greater supplier of protein and lipid end-digestion products. Poached and omelet, however, offer a high net supply of bioaccessible vitamin D3 for elders.