High-Yield Synthesis of Transglycosylated Mogrosides Improves the Flavor Profile of Monk Fruit Extract Sweeteners.

Luo Han Guo fruit extract (Siraitia grosvenorii), mainly composed of mogroside V (50%), could be considered a suitable alternative to free sugars; however, its commercial applications are limited by its unpleasant off-notes. In the present work, a central composite design method was employed to optimize the transglycosylation of a mogroside extract using cyclodextrin glucosyltransferases (CGTases) from three different bacteriological sources (Paenibacillus macerans, Geobacillus sp., and Thermoanaerobacter sp.) considering various experimental parameters such as maltodextrin and mogroside concentration, temperature, time of reaction, enzymatic activity, and pH. Product structures were determined by liquid chromatography coupled to a diode-array detector (LC-DAD), liquid chromatography-electrospray ionization-mass spectrometry (LC-ESI-MS), and matrix-assisted laser desorption ionization time-of-flight mass spectrometry (MALDI-TOF MS). Sensory analysis of glucosylated mogrosides showed an improvement in flavor attributes relevant to licorice flavor and aftereffect. Consequently, an optimum methodology was developed to produce new modified mogrosides more suitable when formulating food products as free sugar substitutes.

Behaviour of citrus pectin and modified citrus pectin in an azoxymethane/dextran sodium sulfate (AOM/DSS)-induced rat colorectal carcinogenesis model.

Large intestine cancer is one of the most relevant chronic diseases taking place at present. Despite therapies have evolved very positively, this pathology is still under deep investigation. One of the recent approaches is the prevention by natural compounds such as pectin. In this paper, we have assessed the impact of citrus pectin and modified citrus pectin on colorectal cancer in rats (Rattus norvegicus F344) to which azoxymethane and DSS were supplied. The lowest intake of food and body weight were detected in animals fed with citrus pectin, together with an increase in the caecum weight, probably due to the viscosity, water retention capacity and bulking properties of pectin. The most striking feature was that, neither citrus pectin nor modified citrus pectin gave rise to a tumorigenesis prevention. Moreover, in both, more than 50% of rats with cancer died, probably ascribed to a severe dysbiosis state in the gut, as shown by the metabolism and metagenomics studies carried out. This was related to a decrease of pH in caecum lumen and increase in acetate and lactic acid levels together with the absence of propionic and butyric acids. A relevant increase in Proteobacteria (Enterobacteriaceae) were thought to be one of the reasons for enteric infection that could have provoked the death of rats and the lack of cancer prevention. However, a reduction of blood glucose and triacylglycerides level and an increase of Bifidobacterium and Lactobacillaceae were found in animals that intake pectin, as compared to universal and modified citrus pectin feeding.

Glycation affects differently the main soybean Bowman-Birk isoinhibitors, IBB1 and IBBD2, altering their antiproliferative properties against HT29 colon cancer cells.

Naturally-occurring serine protease inhibitors of the Bowman-Birk family, particularly abundant in legume seeds, exert their potential chemopreventive and/or therapeutic properties via protease inhibition. Processing of legume seeds, including soybeans, has been proposed as a major cause for their loss of bioactivity due to glycation. In order to assess how glycation affected the protease inhibitory activities of major soybean Bowman-Birk isoinhibitors (BBI) and their antiproliferative properties, IBB1 and IBBD2 were purified and subjected to glycation under controlled conditions using glucose at high temperature. Both soybean isoinhibitors showed remarkable heat stability. In the presence of glucose, IBBD2 lost most of its trypsin inhibitory activity while IBB1 maintains similar trypsin and chymotrypsin inhibitory activities as in the absence of sugar. Glycation patterns of both BBI proteins were assessed by MALDI-TOF spectrometry. Our results show that the glycation process affects IBBD2, losing partially its antiproliferative activity against HT29 colon cancer cells, while glycated-IBB1 was unaffected.

Morphological, technological and nutritional properties of flours and starches from mashua (Tropaeolum tuberosum) and melloco (Ullucus tuberosus) cultivated in Ecuador.

Morphological, technological and nutritional analyses were done in two scarcely studied starches from Andean tubers (mashua and melloco). The low sedimentation values, and the high zeta potential of mashua and melloco starches in cold dispersions, as consequence of their electronegativity, indicated a better behaviour as stabilizer than potato starch. During heating, mashua and melloco starches presented much higher viscosity than potato starch, associated with their higher average particle size and greater amylose content. DSC and TGA analyses indicated that melloco starch had the highest gelatinization enthalpy ΔHgel (12.32 J g-1) and degradation temperature (270 °C), in comparison with potato starch, which are indicators of a better thermal resistance. Consequently, extracted mashua and melloco starches could be excellent and cost-effective thickening or gelling agents in both foods and a wide range of biomaterials. Mashua and melloco starches exhibited a digestion rate close to 80%, which agreed with the low resistant starch content.

Structural and Rheological Properties of Pectins Extracted from Industrial Sugar Beet By-Products.

In this work, the efficient extraction of pectin from sugar beet by-products (pressed, ensiled and dried pulp), by using an acid method or a commercial cellulose, is accomplished. The extraction method had an impact on the pectin monomeric composition, mainly in xylose, arabinose, and galacturonic acid content, as determined by GC-FID. FTIR and SEC analyses allowed the determination of similar degrees of methoxylation and molecular weights, respectively, in the extracted pectins. The acid extraction of pectin in the ensiled by-product led to the highest yield (19%) with a galacturonic acid content of 46%, whereas the application of the enzymatic extraction method resulted in a lower yield (13%) but higher galacturonic acid content (72%). Moreover, the stability in aqueous solution as well as the emulsifying activity index was higher for pectin extracted by the acid method, whereas the viscosity was higher in pectin extracted by the enzymatic method. To the best of our knowledge, this is the first study analyzing the physicochemical properties and exploring the potential reuse of ensiled and dried by-products from sugar beet industry for the extraction of pectin to be further used in the food and pharmaceutical areas.

Behaviour of citrus pectin during its gastrointestinal digestion and fermentation in a dynamic simulator (simgi®).

The behaviour of citrus pectin during digestion and its potential prebiotic properties were examined using a Dynamic Gastrointestinal Simulator (simgi®) model for the human gut, which simulates processes in the stomach, small intestine, ascending, transverse and descending colon. A remarkable non-digestibility of pectin in the upper gastrointestinal tract was observed by HPLC-ELSD analysis, where ∼88% of citrus pectin remained intact during its transit through the stomach and small intestine. Fermentation of pectin stimulated the growth of beneficial bacteria such as Bifidobacterium spp, Bacteroides spp and Faecalobacterium prausnitzii. High increases of short-chain fatty acids (SCFA) were observed, especially in acetate and butyrate concentration due to direct fermentation of pectin or by cross-feeding interaction between bacteria. This is the first study on the digestibility and fermentation of pectin carried out in a complex dynamic gastrointestinal simulator, being of special relevance the results obtained for F. prausnitzii.

Chemical and physicochemical characterization of orange by-products derived from industry.

BACKGROUND: Industrial extraction of orange juice produces a large amount of waste that affects the environment and gives rise to important economic losses; at the same time, information about the composition of the waste is still limited. The present study carried out an exhaustive chemical and physicochemical characterization of the residues in the waste, aiming to increase their potential application for the extraction of functional ingredients. RESULTS: Four different products (three solids and one liqueur) were provided by the industry. The overall characterization indicated that carbohydrates comprised the main components. During processing, carbohydrate derivatives were formed such as those corresponding to the initial steps of the Maillard reaction. In this sense, furosine was demonstrated to be a suitable indicator with respect to the control of the process. Although the phenolic content substantially decreased (by up to 57%) as the processing proceeded, the antioxidant capacity was affected to a much lesser extent (∼10%). Dehydrated products were rich in galacturonic acid and hardly any change was detected during their elaboration. The liqueur by-product was found to have a much higher level of fructose than glucose and sucrose. CONCLUSION: Orange juice waste obtained industrially under the conditions described in the present study could be used as a source of pectic derivatives or fructose in the case of solid or liquid by-products, respectively. The results reported here could diversify the present application of these products as a source of food ingredients, contributing to an improvement in their utilization. © 2018 Society of Chemical Industry.

Anti-inflammatory bowel effect of industrial orange by-products in DSS-treated mice.

This work addresses the role of different by-products derived from the industrial extraction of orange juice in a possible anti-inflammatory effect in mice with colitis induced by dextran sulfate sodium (DSS). Fresh orange residue (FOR), dry orange residue (DOR), orange liqueur (OL) and animal feed (AF), as well as commercial citrus pectin (CP), were administered to C57BL/6J mice for 15 days before starting the DSS treatment. Analysis of macroscopic parameters such as the Disease Activity Index (DAI) and the colonic weight/length ratio revealed an anti-inflammatory effect following intake of FOR, AF or CP. Moreover, q-PCR of RNA from colonic tissue indicated measurable changes in the expression of TNF-α, IL-1ß, iNOS, and intercellular adhesion molecules ICAM I, as well as in intestinal barrier proteins such as MUC-3, occludin, and ZO-1. Pectin, phenolic compounds and/or Maillard reaction products formed at initial steps were identified as relevant components exerting the ascribed beneficial effects. Our findings could open up the further application of a variety of orange by-products as food supplements in the potential amelioration of inflammatory bowel diseases.

Application of a commercial digestive supplement formulated with enzymes and probiotics in lactase non-persistence management.

Strategies to avoid lactose malabsorption, which affects 70% of the world's population, are focused on the restriction of milk and dairy products or the use of non-human ß-galactosidases or probiotics endowed with ß-galactosidase activity added at mealtime. Our evaluation of a commercial blend of probiotics and enzymes (protease, lactase, lipase and amylase) and its potential application in lactase non-persistence management is described in this work. Recommended amounts (460-1000 mg) of the commercial probiotics-enzyme blend were shown to be adequate for performing in vitro lactose hydrolysis in standard solutions (0.25-5%) and commercial dairy products, namely milks (5% lactose) and yogurts (3% lactose), reaching hydrolysis values between 44 and 96%. According to these percentages, the use of the enzymatic preparation would guarantee the intake of less than 12 g, the recommendation of the EFSA for lactose intolerance. Furthermore, formation of prebiotic galactooligosaccharides was also detected, increasing the potential benefits of the enzymatic preparation in the gastrointestinal system.

In vitro fermentation properties of pectins and enzymatic-modified pectins obtained from different renewable bioresources.

The suitability of artichoke and sunflower by-products as renewable sources of pectic compounds with prebiotic potential was evaluated by studying their ability to modulate the human faecal microbiota in vitro. Bacterial populations and short-chain fatty acid (SCFA) production were measured. Reduction of the molecular weight of artichoke pectin resulted in greater stimulation of the growth of Bifidobacterium, Lactobacillus and Bacteroides/Prevotella, whilst this effect was observed only in Bacteroides/Prevotella for sunflower samples. In contrast, the degree of methoxylation did not have any impact on fermentability properties or SCFA production, regardless of the origin of pectic compounds. Although further in vivo studies should be conducted, either pectin or enzymatically-modified pectin from sunflower and artichoke by-products might be considered as prebiotic candidates for human consumption showing similar ability to promote the in vitro growth of beneficial gut bacteria as compared to well-recognized prebiotics such as inulin or fructo-oligosaccharides.

Modification of citrus and apple pectin by power ultrasound: Effects of acid and enzymatic treatment.

Pectin-derived oligosaccharides are emerging as a new generation of functional ingredients with new or improved technological and/or bioactive properties as compared to pectin. This work addresses the impact of power ultrasound (US) on the structure of citrus and apple pectin under different experimental conditions of power, amplitude and pectin concentration in aqueous and acid media, as well as in the presence of a pectinase. Results indicated that depolymerisation of both pectin increased with time and intensity of US in aqueous media and their polydispersity decreased. In general, a higher depolymerisation was observed in pectin treated by US in the presence of nitric and citric acids than in water, and hardly any difference was detected between both types of acids. Most of the assays gave rise to high-methoxylated pectin with a degree of esterification above 50%, pointing out their suitability for potential gelling agents. Finally, US did not have any impact in assisted enzymatic hydrolysis on the degree and/or rate of depolymerisation at low and medium levels of pectin concentration (0.5 and 2%), whereas a higher diversity of pectin fragments was found at 5% which could be indicative of a more controlled depolymerisation. These findings highlight the importance of the selection of appropriate US processing conditions to diversify the applications of modified pectin, as well as the potential of US as a prospective alternative to currently used depolymerisation techniques.

Acute toxicological studies of the main organosulfur compound derived from Allium sp. intended to be used in active food packaging.

Some plant extracts have been proposed as potential alternative to the use of synthetic preservatives in the food industry. Among those, extracts from Allium species exhibit interesting antimicrobial and antioxidant properties for the food packaging industry. The present work aims to assess the usefulness and potential safety of the major organosulfur compound present in a commercial Allium sp. extract (PROALLIUM AP®), namely propyl thiosulfinate oxide (PTSO). For this purpose, its antimicrobial activity was studied in a wide range of microorganisms. Moreover, cytotoxicity and ultrastructural cellular damages caused by PTSO were studied in two human cell lines, Caco-2 and HepG2, being the colonic cells more sensitive to this compound. Finally, the protective role of PTSO against an induced oxidative situation was evaluated in the human intestinal Caco-2 cells. The results revealed damage at high concentration, although no significant adverse effects were recorded for the concentration to be used in food packaging. Moreover, the in vivo study also revealed the potential safety use at the established concentrations. In addition, the antimicrobial properties and the antioxidant role of PTSO were confirmed. Therefore, this compound could be considered as a good natural alternative to synthetic preservatives used in the food packaging industry.

Cytotoxic and mutagenic in vitro assessment of two organosulfur compounds derived from onion to be used in the food industry.

Edible members of the Allium family are widely used since they exhibit antioxidant and antibacterial related to the organosulphur compounds. One the most promising use of Allium species, hence, onion essential oil, could be in the packaging food industry. The present work aims to assess the safety of two organosulphur compounds present in onion essential oil; dipropyl disulphide, dipropyl sulphide and their mixture. For this purpose, cytotoxicity, reactive oxygen species and glutathione contents, and ultrastructural cellular damages were studied in the human intestinal cells, Caco-2, exposed to these organosulphur compounds. Moreover, their potential mutagenicity was also assessed. The results revealed no significant adverse effects. Additionally, reactive oxygen species scavenger activity was observed for both compounds. Therefore, they could be a good natural alternative to other synthetic antioxidant and antibacterial substances used in the food industry.

Structural differences of prebiotic oligosaccharides influence their capability to enhance iron absorption in deficient rats.

This study evaluates the influence of novel galacto-oligosaccharides derived from lactulose (GOS-Lu), kojibiose or 4'-galactosyl-kojibiose in hematological parameters of Fe homeostasis using Fe-deficient animals. Liver TfR-2, IL-6, NFκB and PPAR-γ expression (mRNA) were also determined by RT-qPCR analyses, and active hepcidin peptide production and short chain fatty acids by LC coupled to MS/MS or UV detection. Feeding animals with GOS-Lu or kojibiose together with FeCl3 increased hemoglobin (Hb) production (by 17%) and mean Hb concentration into erythrocytes relative to animals administered with FeCl3 alone (14.1% and 19.7%, respectively). Animals administered with prebiotics showed decreased plasmatic hepcidin levels, contributing to a higher intestinal absorption of the micronutrient. These data indicate that concurrent administration of these potentially prebiotic oligosaccharides together with a supplement of Fe ameliorates inflammation-mediated perturbations in the liver, according to the particular structure of the prebiotic compound, and result an attractive strategy to improve Fe absorption.

Assessment of initial stages of Maillard reaction in dehydrated onion and garlic samples.

The initial steps of the Maillard reaction in freshly laboratory-freeze-dried and commercial dehydrated onion and garlic samples have been assessed by quantitative determination of 2-furoylmethylamino acids, obtained after acid hydrolysis of the corresponding Amadori compound. In freshly prepared samples, hardly any presence of 2-furoylmethylamino acids was detected, whereas in commercial samples, onion contained much more important levels of 2-furoylmethylamino acids as compared to garlic species. 2-Furoylmethyl-gamma-aminobutyric acid (1), 2-furoylmethyl-lysine (furosine; 2), and 2-furoylmethylarginine (3) were identified in all commercial dehydrated onion samples, with compound 3 being the most abundant. All garlic samples presented slightly higher levels of 2 than 3 with no presence of 1. The observed differences between onion and garlic commercial samples may be due to their very different content of reducing sugars. Moreover, some variations found in 2-furoylmethyl derivatives within both onion and garlic species could be also attributed to different processing and storage conditions during the manufacture of these products. The findings of this study show the first evidence of important levels of Amadori compounds in dehydrated garlic and onion samples, as well as the usefulness of 2-furoylmethyl derivatives as quality indicators for the early detection of the Maillard reaction in onion and garlic products.