Exploring Maillard reaction markers and melanoidins to investigate toxicological and antioxidant profiles of optimized expanded snacks from corn/common bean mixtures.

BACKGROUND: Extrusion cooking of cereal-legume flour mixture is an innovative strategy to introduce nutrient-enriched ready-to-eat snacks to the market. However, this thermal process triggers the formation of compounds that could impact safety aspects of these products. Maillard reaction markers and the end products known as melanoidins were evaluated to assess the toxicological and bioactive profiles of extruded snacks from corn-plus-common-bean-flour combinations. Different molecular weight fractions were isolated and purified to analyze their antioxidant activity and to investigate the role of melanoidins. RESULTS: The snack formulated with an 84:16 ratio of corn:common bean flours exhibited an enhanced toxicological profile. It displayed the lowest levels of acrylamide and furanic compounds, along with reduced blockage of lysine residues in the protein. Extrusion increased the antioxidant activity of uncooked flours (30 to 64%) and total phenolic compounds (26 to 50%), and decreased the available lysine (-72.7 to -79.5%). During the fractionation process, it was established that compounds within the range of 3-10 kDa made the greatest contribution to antioxidant activity. The fraction greater than 10 kDa, which included melanoidins, displayed 7 to 33% lower antioxidant activity. The purification of the fraction greater than 10 kDa revealed that pure melanoidins represented approximately one-third of the antioxidant activity in that fraction. Non-covalent adducts linked to the melanoidin core therefore had a relevant role in the antioxidant action of formulated snacks. CONCLUSION: This investigation illustrates the importance of considering both potential risks and associated benefits of compounds formed during the Maillard reaction while developing new extruded snacks. © 2024 The Author(s). Journal of The Science of Food and Agriculture published by John Wiley & Sons Ltd on behalf of Society of Chemical Industry.

Skeletal muscle proteome of piglets is affected in a muscle-dependent manner by a limiting total sulfur amino acid supply.

PURPOSE: A total sulfur amino acid (TSAA) deficient diet can affect the amino acid composition of skeletal muscles. However, it is unknown how the different muscle proteins are affected by the TSAA deficiency. METHODS: The proteomic profiles of the fast-twitch glycolytic longissimus (LM) and the slow-twitch oxidative rhomboideus (RM) muscles were compared in 42-day-old piglets fed either a 28% deficient (TSAA-) or a sufficient (TSAA+) diet in TSAA for 10 days. Differentially regulated proteins were identified and submitted to Gene Ontology Pathways Analysis to identify biological processes affected by TSAA deficiency. RESULTS: A total of 36 proteins in LM and 24 proteins in RM differed in abundance between the two dietary treatments. In both muscles, an increased oxidative energy metabolism was observed in TSAA- piglets. However, a greater mitochondrial oxidation of pyruvate generated from glycolysis was observed in LM of TSAA- piglets, whereas fatty acid ß-oxidation and glycogen sparing were favored in RM. This suggests a muscle-specific reorientation of energy metabolism in response to a TSAA- deficiency. In both muscles, the protein abundance and enzyme activity of superoxide dismutase were increased in TSAA- piglets. Other enzymes involved in antioxidant defense, heat shock proteins coping with cellular stress, and annexins involved in the regulation of apoptosis were generally found to be more expressed in the LM of TSAA- piglets, with no or minor changes in RM. CONCLUSIONS: Skeletal muscle proteome in young growing piglets was modulated in a muscle-dependent manner by a deficient TSAA supply, with accentuated changes in fast-twitch glycolytic muscle.

Alternative food matrices for snack formulations in terms of acrylamide formation and mitigation.

BACKGROUND: The salty snack market is re-inventing itself trying to offer to consumers healthier and added-value products often based on alternative vegetables/cereals, such as vegetable chips. New options mostly involve a nutritional improvement but the toxicological aspects of the reformulation are not usually examined. This work evaluated the acrylamide formation and effectiveness of different mitigation strategies in potato chips and in alternative snacks, such as carrot and pumpkin chips. Fresh potato, carrot and pumpkin samples were fried under controlled conditions and after being subjected to different operations (soaking in water at different times/temperatures, adding lemon or vinegar as pH modifiers or salt). RESULTS: Acrylamide values in control samples of carrot (224 ± 47 µg kg-1 ) and pumpkin (514 ± 83 µg kg-1 ) were significantly lower than in the potato chip samples (3887 ± 509 µg kg-1 ). The different mitigation treatments had effects on potato and pumpkin chips, the most effective strategies being soaking options and the decrease of the pH of the medium. However, such treatments were not as effective in carrot chips. CONCLUSIONS: These new vegetable snacks could be a healthy alternative both at nutritional and toxicological level. In addition, acrylamide concentration could even be reduced with simple mitigation operations before frying. © 2018 Society of Chemical Industry.

Effect of different cooking methods on nutritional value and antioxidant activity of cultivated mushrooms.

Influence of culinary treatments (boiling, microwaving, grilling, and deep frying) on proximate composition and antioxidant capacity of cultivated mushrooms (Agaricus bisporus, Lentinula edodes, Pleurotus ostreatus, and Pleurotus eryngii) was studied. Proximate composition was affected by the cooking method and the mushrooms species. Frying induced more severe losses in protein, ash, and carbohydrates content but increased the fat and energy. Boiling improved the total glucans content by enhancing the ß-glucans fraction. A significant decrease was detected in the antioxidant activity especially after boiling and frying, while grilled and microwaved mushrooms reached higher values of antioxidant activity. Maillard reaction products could be partially responsible, as supported by the absorbance values measured at 420 nm. Since cooking techniques clearly influence the nutritional attributes of mushrooms, the proper selection of treatments is a key factor to prevent/reduce nutritional losses. Microwaving and grilling were established as the best processes to maintain the nutritional profile of mushrooms.

Do bread-crust-derived Maillard reaction products affect the retention and tissue distribution of trace elements?

PURPOSE: To investigate the effects of the consumption of Maillard reaction products (MRPs) from bread crust (BC) on iron, copper and zinc body retention and tissue distribution, determining whether these effects are related to the molecular weight of browning products. METHODS: During an 88-day study period, rats were fed a Control diet or diets containing BC as source of MRPs, its soluble high or low molecular weight fractions (BC, LMW or HMW diets). A mineral balance was conducted throughout the experiment to determine iron, copper and zinc retention. At day 88, animals were killed, blood was drawn for haemoglobin determination and some organs removed to analyse minerals. RESULTS: Copper and zinc balances were unchanged, and scant modification detected in their body delivery. However, the Fe retention rate from the diet increased (13, 22 and 32 % for BC, LMW and HMW diets), and a parallel higher Fe body concentration was observed (13-18 % higher than the Control group). Incoming iron accumulated particularly in the liver, femur and small intestine, but functional iron tended to decrease, as reflected by haemoglobin levels. CONCLUSIONS: The long-term intake of BC or derivatives did not produce a notable effect on copper or zinc balances, although slightly increased iron retention rate and the body concentration of this mineral were observed. Iron accumulated in some organs, but the production of haemoglobin was not improved. In view of the differences observed between the effects of BC and its derivatives, our results underline the importance of working with real food matrices, where the joint presence of different components modulates the in vivo final effects.

Maillard reaction products: some considerations on their health effects.

For several decades, researchers have been investigating the relations between the consumption of Maillard reaction products (MRPs) and biological activities, whether harmful or beneficial. Interest in this area is growing because the intake of these compounds has increased in parallel with the consumption of thermally processed foods. MRPs are bioavailable to some degree and, although there is little consensus about possible harmful effects or pathways of action, there are pathological implications regarding the progress and development of various degenerative disorders. Besides these considerations, it has been reported that some MRPs, particularly melanoidins, have beneficial effects as antioxidant, anti-inflammatory or anti-aging factors, among others. Some interesting aspects of this dual nature of MRPs are addressed in the present review. In this context, it is difficult to draw firm conclusions about the physiological consequences resulting from MRPs intake, due to the diversity of compounds formed in the different food matrixes. Maintaining a balanced and varied diet, not only in the food consumed but also in how it is processed, is increasingly viewed as the best strategy to limit the negative effects and to preserve the positive actions of dietary MRPs. Much remains to be done to elucidate the chemical structures of these compounds and to relate it to specific physiologic actions. For that purpose, setting the chromatographic determinations as the most reliable analytical tools to measure them in foods and biological tissues/fluids seems essential. Moreover,designing more realistic and better controlled clinical studies, based on the real diet of the population, will be the only method to perform an effective health-risk assessment of MRPs consumption.

Chickpea Seed Flours Improve the Nutritional and the Antioxidant Profiles of Traditional Shortbread Biscuits: Effects of In Vitro Gastrointestinal Digestion.

Functional gluten-free biscuits enriched with commercial and landrace non-commercial chickpea flours were designed and compared with a traditional shortbread biscuit. They were analyzed in sensory attributes, amino acid profile, and antioxidant properties. Subsequently, the biscuits were digested in vitro to evaluate protein hydrolysis, amino acid bioaccessibility, phenolic compounds release, and antioxidant markers. The presence of chickpea flours provided golden color and heightened biscuit hardness and fracturability (especially in non-commercial), increasing crispness and reducing brittleness. The protein hydrolysis was similar among samples (≈15%), except for one of the non-commercial (≈20%). Amino acids such as arginine, phenylalanine, leucine, tyrosine, and lysine exhibited the highest bioaccessibilities. Incorporating chickpea flour improved the antioxidant activity and polyphenol content in undigested samples and bioaccesible fractions, with higher levels of p-coumaric and ferulic acids after digestion, regardless of the chickpea seed. Non-commercial flours increased the presence of resveratrol and/or catechin in the bioaccessible fraction. Antioxidant action assessed in the Caco-2 cell line showed that the protective effect against reactive oxygen species (ROS) generation did not always correlate with the in vitro antioxidant capacity. Our data support that the inclusion of chickpea flours in the formulation of functional biscuits provides the consumer with products of added nutritional value with attractive organoleptic features.

Effects of dietary bread crust Maillard reaction products on calcium and bone metabolism in rats.

Maillard reaction products (MRP) consumption has been related with the development of bone degenerative disorders, probably linked to changes in calcium metabolism. We aimed to investigate the effects of MRP intake from bread crust on calcium balance and its distribution, and bone metabolism. During 88 days, rats were fed control diet or diets containing bread crust as source of MRP, or its soluble high molecular weight, soluble low molecular weight or insoluble fractions (bread crust, HMW, LMW and insoluble diets, respectively). In the final week, a calcium balance was performed, then animals were sacrified and some organs removed to analyse calcium levels. A second balance was carried out throughout the experimental period to calculate global calcium retention. Biochemical parameters and bone metabolism markers were measured in serum or urine. Global calcium bioavailability was unmodified by consumption of bread crust or its isolate fractions, corroborating the previously described low affinity of MRP to bind calcium. Despite this, a higher calcium concentration was found in femur due to smaller bones having a lower relative density. The isolate consumption of the fractions altered some bone markers, reflecting a situation of increased bone resorption or higher turnover; this did not take place in the animals fed the bread crust diet. Thus, the bread crust intake does not affect negatively calcium bioavailability and bone metabolism.

Consumption of model maillard reaction products has no significant impact on Ca and Mg retention or on tissue distribution in rats.

Our aim was to analyze the influence of the prolonged consumption of Maillard reaction prod-ucts (MRPs) from the glucose-lysine model system, on calcium and magnesium bioavailability and on tissue distribution in female rats. A long-term study (88 days) was conducted, in which two groups of rats (n = 12) were fed either a Control diet or one including 3 % glucose-lysine MRPs (GL90 diet). During the experimental period, the global balance was determined; calcium apparent absorption, retention, and bioavailability were stable after consumption of the assayed MRPs (37 % and 38 % for the Control and GL90 groups, respectively). Consequently, there was no change in calcium tissue distribution. During the final week, an additional balance was performed, following urine and feces collection, which showed calcium bioavailability to be stable. During the same period, magnesium apparent absorption and retention increased, leading to higher digestibility and bioavailability. However, these variations could be isolated events of little significance, since overall there were no variations in magnesium body content or retention (73 mg and 75 mg for the Control and GL90 groups, respectively). This conclusion was supported by the stability of the magnesium content and its concentration in the organs. These findings are in line with those of previous studies, which have reported the low affinity of these metals to form MRP complexes.

Influence of Maillard products from bread crust on magnesium bioavailability in rats.

BACKGROUND: Consumption of Maillard reaction products (MRPs) present in food has been related to deterioration of protein digestibility and changes in mineral bioavailability. We aimed to investigate the effects of MRP intake from bread crust on magnesium balance and tissue distribution, seeking causative factors among its different components. RESULTS: During the final stage of the trial, magnesium digestibility improved by around 15% in rats fed diets containing bread crust or its derivatives compared with the control diet. Despite certain enhancements in magnesium bioavailability in this stage, for the experimental period as a whole, this parameter remained unchanged. However, specific changes in the content and/or concentration in some organs were observed, particularly in the femur, where magnesium levels were higher due to the smaller size of the bones. CONCLUSIONS: Consumption of MRPs from bread crust or its different components did not modify the magnesium balance. Nevertheless, the bread crust fractions led to some changes in magnesium tissue distribution which did not match the effects induced by complete bread crust intake, suggesting the importance of designing studies with real-food systems, in order to reinforce the validity of the findings obtained.

Effects of model Maillard compounds on bone characteristics and functionality.

BACKGROUND: Physical and biomechanical properties of bone can be affected by non-enzymatic crosslinks, which are implicated in bone pathologies such as osteoporosis. The purpose of this study was to analyse the effects of the consumption of model Maillard reaction product (MRP) from glucose-lysine heated for 90 min at 150 °C (GL90) on bone composition and features. Rats were fed either a control diet or a diet containing 30 g kg(-1) GL90 for 88 days. Food consumption and the animals' body weights were monitored. After sacrifice, the femur, pelvic bone and tibia were removed for analysis of their composition and physical and biomechanical properties. RESULTS: The organic matrix of the femur and the density of the pelvic bone decreased after MRP intake, whereas pentosidine content increased greatly with respect to the control group (41.7 ± 9.9 vs 171.4 ± 3.3 mmol mol(-1) collagen). The rising level of C-telopeptide degradation products from type I collagen (ß-CTX) suggested a possible situation of increased bone resorption and/or higher turnover. CONCLUSION: In conjunction, the detrimental effect on the organic matrix, the situation of higher resorption and/or bone turnover indicated by the ß-CTX values and the high pentosidine content in bone provoked negative consequences on certain mechanical properties such as the ability to withstand force and absorb energy without failure.

Assessment of dietary acrylamide exposure in children attending Spanish school canteens using the duplicate diet method.

Acrylamide is a carcinogenic chemical contaminant formed in heat-treated foods. In this study, a duplicate diet method was used to evaluate the acrylamide content of foods/meals served at breakfast and lunch in two Spanish school canteens. The dietary acrylamide intake in students was estimated within lower bound (LB) and upper bound (UB) scenarios. Biscuits exhibited the highest acrylamide values, exceeding the benchmark level established by the European Regulation 2017/2158 (350 µg/kg), followed by main courses such as stews, side dishes and bread. In the LB scenario, breakfasts accounted for the major contributors to the daily acrylamide intake (73.3%). However, lunches were the main responsible in the UB scenario (65.4%). Acrylamide exposure was estimated for three age ranges: 3-5y pre-school children (0.59 and 0.92 µg/kg body weight/day), 6-9y children (0.43 and 0.67 µg/kg body weight/day) and 10-12y early adolescents (0.28 and 0.44 µg/kg body weight/day). Margins of exposure for neoplastic effects ranged between 144 and 1026, which is below the reference of 10,000, indicating a health concern. The findings reveal that any diet, even one that is balanced, varied and contains foods low in acrylamide, involves an additive exposure to the contaminant that should be considered when conducting acrylamide exposure risk assessments.

Dietary Exposure to Acrylamide in Spanish University Canteens by the Duplicate Diet Method.

During the university period, many students adopt new dietary patterns, sometimes including the excessive consumption of highly processed foods, which can expose them to process contaminants such as acrylamide. This research aimed to evaluate the dietary exposure to acrylamide of Spanish university students in their campus canteens using the duplicate diet method, and to estimate the associated health risks based on their food consumption habits. Apart from potato-based foods, the analysed food/meals contained non-detectable or low levels of acrylamide (<63 µg/kg). Two exposure scenarios were considered, depending on whether students selected salad (lowest exposure) or processed potatoes (highest exposure) as side dishes. The frequent consumption of processed potatoes could increase acrylamide intake from 6.5 to 26.4 µg/day. Due to their lower body weight, women had a higher risk of acrylamide exposure in both scenarios. The margin of exposure (MOE) values for neoplastic effects indicated high levels of health concern, even only considering the main meal of the day. Furthermore, the risk of acrylamide exposure could increase by more than four times depending on the side dish selected by the students. This research highlights the need to promote healthy dietary habits among young people, encouraging the selection of safer food options in terms of food processing contaminants.

An Updated Review of Soy-Derived Beverages: Nutrition, Processing, and Bioactivity.

The global market for plant-based drinks is experiencing rapid growth driven by consumer demand for more sustainable diets, including vegetarian and vegan options. Soy beverages in particular are gaining popularity among individuals with lactose intolerance and milk protein allergies. They are considered an excellent source of high-quality protein, vitamin B, unsaturated fatty acids, and beneficial phytochemicals such as phytosterols, soy lecithins, and isoflavones. This review presents a comprehensive market survey of fifty-two soy beverages available in Spain and other European countries. The predominant category among those evaluated was calcium and vitamin-fortified drinks, accounting for 60% of the market. This reflects the need to address the nutritional gap compared to cow's milk and meet essential dietary requirements. The review covers the technological aspects of industrial soy milk production, including both traditional methods and innovative processing techniques. Additionally, it analyzes multiple studies and meta-analyses, presenting compelling evidence for the positive effects of soy beverages on various aspects of health. The review specifically examines the contributions of different components found in soy beverages, such as isoflavones, proteins, fiber, and oligosaccharides. Moreover, it explores controversial aspects of soy consumption, including its potential implications for growth, puberty, fertility, feminization, and the thyroid gland.

Study of the urinary and faecal excretion of Nε-carboxymethyllysine in young human volunteers.

The dietary habits of the adolescent population with a high intake of snack and fast foods mean that they consume a high rate of which in turn leads to the development of different degenerative disorders. There are few studies available on MRP absorption and metabolism. We investigated the effects of a MRP-high and a MRP-low diet on carboxymethyllysine (CML) intake and excretion in 11-14 years adolescent males. In a 2-period crossover trial, 20 healthy subjects were randomly assigned to two groups. The first group consumed the MRP-low diet for 2 weeks, observed a 40-day washout period, and then consumed the MRP-high diet for 2 weeks. The second group received the diets in the reverse order. Subjects collected urine and faeces on the last 3 days of each dietary period. The consumption of the MRP-high diet led to a higher CML input (P < 0.05) (11.28 vs. 5.36 mg/day CML for MRP-high and -low diet, respectively). In parallel, the faecal excretion was also greater (P < 0.05) (3.52 vs. 1.23 mg/day CML, respectively) and proportional to the dietary intake. The urinary elimination of CML was not increased significantly when the MRP-high diet was consumed compared to consumption of the MRP-low diet, and was not proportional to the dietary exposure of CML. In conclusion it was shown that CML absorption and faecal excretion were highly influenced by dietary CML levels. Since the compound has long-term effects on health, an excessive intake deserves attention, especially in a population nutritionally at risk as adolescents.

Influence of bread crust-derived Maillard reaction products on phosphorus balance in rats.

BACKGROUND: Maillard reaction products (MRP) improve food palatability and are linked to some positive biological actions. However, diverse negative consequences, some related to protein damage and mineral availability, have been established. AIM OF STUDY: We investigated the effects of MRP, from a bread crust diet, on phosphorus bioavailability and tissue distribution in rats to determine whether these effects are related to the molecular weight of browning products. METHODS: During a study period of 88 days, rats were fed either a control diet or one of the following: with bread crust as a source of MRP, or one with its soluble high molecular weight, soluble low molecular weight or insoluble fraction (bread crust, HMW, LMW and insoluble diets, respectively). In the final week, a phosphorus balance was performed, after which the animals were sacrificed and some organs removed to analyse phosphorus content. A second balance was carried out throughout the experimental period to calculate phosphorus retention. RESULTS: Phosphorus balance in the last week was unchanged. However, considering the whole experimental period, a trend towards improved bioavailability, significant in the HMW group, was observed. Higher phosphorus concentrations were measured in the small intestine and bone. CONCLUSIONS: The consumption of MRP derived from bread did not alter phosphorus retention, due to increased bioavailability, especially concerning HMW compounds. The overall phosphorus body content remained unchanged and there were no changes in the bone, its principal metabolic destination. However, MRP consumption markedly raised phosphorus levels at the digestive level, especially when consumed as isolate fractions. The slower rate of stomach emptying is assumed to be related to this effect.

Acrylamide Exposure from Common Culinary Preparations in Spain, in Household, Catering and Industrial Settings.

In 2019, the European Commission recommended monitoring the presence of acrylamide in certain foods not included in Regulation 2158/2017, to consider other sources of exposure to the contaminant. In the present study, eleven groups of processed foods commonly consumed in Spain were classified, according to their food matrix, into potato-based food, cereal-based food and food based on cereal mixed with meat, fish or vegetables. Samples were collected from three different settings: household, catering services and industrial origin, to evaluate the influence of the food preparation site on acrylamide formation. The highest concentrations of acrylamide were observed in chips (French fries), especially those prepared at home. Although at lower levels, all the other foods also contained significant concentrations of acrylamide, confirming the need to control its content in foods not included in the EU regulation. Industrially processed foods made a lower contribution to acrylamide exposure, probably due to the more stringent controls exercised on culinary processes in this context. The higher levels recorded for households and catering services highlight the need for greater awareness of culinary processes and for measures to be adopted in these settings to limit the formation of acrylamide in food preparation.

Effect of consumer's decisions on acrylamide exposure during the preparation of French fries. Part 2: Color analysis.

Two observational tests were designed to investigate the influence of consumer decisions during the preparation of French fries from fresh potatoes on acrylamide formation. In both tests, color was of paramount importance to volunteers with regards to the decision to stop the frying process. CIE-Lab* color parameters and visual color assessments of French fries were associated with general acrylamide content and its classification according to the EU benchmark levels (BL, 500 µg/kg). Binary logistic regression analysis revealed that color parameter a* was the main factor in determining the probability of acrylamide content being above BL, regardless of the culinary practices applied. A cut-off of 0.855 for a* produced the greatest sensitivity (81.1%) and specificity (99.9%) for classifying samples with acceptable BL of acrylamide content. An increase of one unit of a* more than quadruple the risk of acrylamide content not falling within BL. When no external color reference was provided, volunteers misclassified 33.6% of fries as having a golden color. Harmonized criteria based on a reference color chart that indicates a golden color are necessary for producing fries with reduced acrylamide contents and, in this way, limit the risk of exposure to acrylamide in domestic settings.

Effect of consumer's decisions on acrylamide exposure during the preparation of French fries. part 1: Frying conditions.

Variability in home-cooking practices affects dietary exposure to acrylamide, limiting risk evaluation. Two observational tests (controlled and randomized) involving 127 volunteers was designed to investigate the influence of consumer decisions on acrylamide formation during the preparation of French fries. Consumer practices were recorded during pre-frying, frying and post-frying stages. Reducing sugar content, asparagine, moisture, acrylamide, moisture, weight loss and color were evaluated. In the controlled assay, mean acrylamide content was 508 µg/kg and volunteers took a mean frying time of 91.9 s (87.5-96.4, C.I. 95%). The narrow confidence interval of 8.9 s represented an increase of 120 µg/kg in the acrylamide content of the fried potato. Average acrylamide content in the randomized assay (215 µg/kg, 150-280 µg/kg, C.I. 95%) was significantly lower than in the controlled assay. Amongst the culinary practices applied for the potato variety evaluated, washing of the potato strips significantly reduced acrylamide content in French fries. The percentage of samples with acrylamide lower than the benchmark value (500 µg/kg) was 54% and 93% for the controlled and randomized assays, respectively. Estimated average dietary exposure to acrylamide from French fries in adults was 5.65 µg/day, which corresponds to a margin of exposure of 2105 for carcinogenicity.

Does the pelleting process affect the nutritive value of a pre-starter diet for suckling piglets? Ex vivo studies on mineral absorption.

BACKGROUND: The effects of pelleting on the extent of the Maillard reaction (MR) and on calcium, magnesium and zinc solubility and absorption were analysed in a conventional pre-starter diet for suckling piglets. Development was tested measuring colour, absorbance (280/420 nm), fluorescence, residual free lysine, furosine, hydroxymethylfurfural (HMF) and furfural contents before and after pelleting. Fluorescence, absorbance and mineral solubility were also measured after in vitro digestion of diets. The effects on mineral absorption were tested using Caco-2 cells. RESULTS: MR indexes confirmed the development of the reaction during the pelleting of this particular diet compared with the meal diet. The CIE-Lab colour parameters showed a decrease in luminosity (L*) and progress of the colour to the red zone (a*) in the pelleted diet. A 36% decrease in free lysine content was observed. Significant correlations were observed between fluorescence intensity and furosine levels, HMF and furfural. The pelleting process did not modify calcium and magnesium solubility after in vitro digestion, but soluble zinc increased. The efficiency of calcium and zinc transport across Caco-2 cell monolayers was greater in the pelleted diet. CONCLUSIONS: Evidence of MR development is shown, resulting in various nutritional consequences. Optimisation of pelleting could result in a better formulation of diets for feedstuffs.