BackgroundDeep frying in oil is a popular cooking method around the world. However, the safety of deep-fried edible oil, which is ingested with fried food, is a concern, because the oil is exposed continuously to be re-used at a high temperature, leading to a number of well-known chemical reactions. Thus, this study investigates the changes in energy metabolism, colon histology and gut microbiota in rats following deep-fried oil consumption and explores the mechanisms involved in above alterations.MethodsDeep-fried oil was prepared following a published method. Adult male Wistar rats were randomly divided into three groups (n = 8/group). Group 1: basal diet without extra oil consumption (control group); Group 2: basal diet supplemented with non-heated canola oil (NEO group); Group 3: basal diet supplemented with deep-fried canola oil (DFEO group). One point five milliliters (1.5 mL) of non-heated or heated oil were fed by oral gavage using a feeding needle once daily for 6 consecutive weeks. Effect of DFEO on rats body weight, KEGG pathway regarding lipids metabolism, gut histology and gut microbiota were analyzed using techniques of RNA sequencing, HiSeq Illumina sequencing platform, etc.ResultsAmong the three groups, DFEO diet resulted in a lowest rat body weight. Metabolic pathway analysis showed 13 significantly enriched KEGG pathways in Control versus NEO group, and the majority of these were linked to carbohydrate, lipid and amino acid metabolisms. Comparison of NEO group versus DFEO group, highlighted significantly enriched functional pathways were mainly associated with chronic diseases. Among them, only one metabolism pathway (i.e. glycerolipid metabolism pathway) was found to be significantly enriched, indicating that inhibition of this metabolism pathway (glycerolipid metabolism) may be a response to the reduction in energy metabolism in the rats of DFEO group. Related gene analysis indicated that the down-regulation of Lpin1 seems to be highly associated with the inhibition of glycerolipid metabolism pathway. Histological analysis of gastrointestinal tract demonstrated several changes induced by DFEO on intestinal mucosa with associated destruction of endocrine tissue and the evidence of inflammation. Microbiota data showed that rats in DFEO group had the lowest proportion of Prevotella and the highest proportion of Bacteroides among the three groups. In particular, rats in DFEO group were characterized with higher presence of Allobaculum (Firmicutes), but not in control and NEO groups.ConclusionThis study investigated the negative effect of DFEO on health, in which DFEO could impair glycerolipid metabolism, destroy gut histological structure and unbalance microbiota profile. More importantly, this is the first attempt to reveal the mechanism involved in these changes, which may provide the guideline for designing health diet.Electronic supplementary materialThe online version of this article (doi:10.1186/s12944-016-0252-1) contains supplementary material, which is available to authorized users.

(2017) Effect of interactions between starch and chitosan on waxy maize starch physicochemical and digestion properties, CyTA -Journal of Food, 15:3, 327-335, DOI: 10.1080/19476337.2016 To link to this article: https://doi.org/10. 1080/19476337.2016 Physicochemical and digestion properties of chitosan modified starch prepared by dry heat treatment were investigated. Starch granule aggregation occurred following the addition of chitosan and this trend was enhanced with increasing chitosan concentration. The size of chitosan modified starch particles was about six times of that of the native starch granules. Interactions between the hydroxyl groups of starch and the amino groups of chitosan was confirmed by Fourier transform infrared spectroscopy analysis. The disappearance of the trough in the Rapid Visco Analyzer profile indicated that the cross-links increased the starch shear resistance. The cross-links between starch and chitosan also reduced starch digestion rate compared to the control (p < 0.001), and this reduction was further enhanced with an increasing chitosan concentration. Additionally, the addition of chitosan altered starch digestion kinetics from one phase to two phases, implying that chitosan modification changed both starch structure and its digestion behaviors.Efecto de las interacciones entre el almidón y el chitosán en las propiedades fisicoquímicas y digestivas del almidón de maíz ceroso RESUMEN Se investigaron las propiedades fisicoquímicas y digestivas del almidón modificado con chitosán preparado mediante tratamiento de calor seco. El agregado de gránulos de almidón ocurrió después de la adición de chitosán y esta tendencia mejoró con el aumento en la concentración de chitosán. El tamaño de las partículas de almidón modificado con chitosán fue alrededor de 6 veces mayor que aquel de los gránulos de almidón nativos. Se confirmaron las interacciones entre los grupos hidroxilo del almidón y los grupos amino del chitosán mediante el análisis espectroscópico de infrarrojos de transformada de Fourier. La desaparición de la canalización en el perfil del analizador de viscosidad (RVA) indicó que la reticulación produjo un aumento en la resistencia al corte del almidón. La reticulación entre el almidón y el chitosán también redujo el ritmo digestivo del almidón en comparación con la muestra control (p < 0,001). Esta reducción fue posteriormente mejorada con un aumento en la concentración de chitosán. Además, la adición de chitosán alteró la cinética digestiva del almidón de una a dos fases, implicando que la modificación con chitosán comportó cambios en la estructura y comportamiento digestivo del almidón. ARTICLE HISTORY

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In this study, rats with a fresh oil diet, a deep‐fried oil diet, and a deep‐fried oil and resistant starch (RS) diet were investigated for revealing the effects of deep‐fried oil to the metabolic system and if RS could effectively attenuate metabolic dysfunction caused by deep‐fried oil. The results showed that DO feeding led to significant increases of liver biomarkers of alanine aminotransferase (ALT) and aspartate transaminase (AST), accompanied by consistent reduction of total antioxidation (T‐AOC) and glutathione peroxidase (GSH‐Px) activity compared to the rats feeding with unheated canola oil (FO group) (p < 0.05). Liver histology of rats in DO group exhibited membrane blebbing and boundary ambiguity, indicating DO might exert significant hepatotoxic effects. However, RS intervention (DO‐RS group) significantly reversed these changes. Furthermore, the results in this study revealed that p53 and MAPK signaling pathways presented in the significantly enriched KEGG pathways list in FO versus DO group, but not in FO versus DO‐RS group, suggesting RS intervention modulated these two signaling pathways. This is the first study to investigate RS intervention on the attenuation of hepatotoxicity induced by DO intake in the dietary. Practical applications: This study investigates the toxic effects of deep‐fried oil consumption on health, in particular on hepatic immune system and the related mechanisms involved in this process. The main target of this research work is to contribute with useful information of deep‐fried oil intake to the food industry and to find out effective ways to ameliorate the risk of deep‐fried oil diet. A deep‐fried oil diet can cause hepatotoxicity; in contrast, rats fed a deep‐fried oil and RS diet are protected. The modulation of p53 and MAPK pathways might be one of the key regulations for RS intervention to attenuate liver dysfunction biomarkers (ALT and AST).