Lysine availability is diminished in commercial fibre-enriched breakfast cereals

Spent coffee grounds as feedstock for the production of biosurfactants and the improved recovery of melanoidins

Spent coffee grounds (SCG) are wastes generated in high amounts worldwide. Their composition makes them a promising feedstock for biotechnological processes. Here we show that the production of the biosurfactant surfactin by submerged culture of a Bacillus subtilis strain growing on SCG is possible, reaching concentrations up to 8.8 mg/L when using SCG at 8.3 g/L in the medium. In addition, we report a synergy between the production of surfactin and the recovery of melanoidins, an added-value compound already present in SCG. More specifically, the concentration of melanoidins in the culture medium increased between 2.1 and 2.5 times thanks to the presence of the B. subtilis in the culture. Furthermore, we have observed a strong interaction between surfactin and melanoidin aggregates through dynamic light scattering measurements, and that both of them can be co-purified with an acid precipitation. We have also characterized the interfacial and antioxidant properties of the cell-free supernatant and surfactin extract, as well as the distribution of the congeners of the biosurfactant. Altogether, this work describes a promising approach to obtain biosurfactants and antioxidant molecules in a single operation, which can be used to design several new formulations of interest for bioremediation, amendment of soils, food and cosmetics.

Effect of in vitro digestion and fermentation on antioxidant capacity of weight loss foods and Maillard reaction products content

Cereal snacks and meal replacement shakes are gaining popularity as part of a low-calorie diet. However, some concerns have been risen in relation to their nutrient content and industrial processing. Here we analyzed 74 products, including cereal bars, cereal cakes and meal replacement shakes. We measured furosine and 5-hydroxymethyl-furfural (HMF) due to their relation with industrial processing, mainly thermal treatment, as well as antioxidant capacity after in vitro digestion-fermentation. Most of the products reported a high sugar content, including also large concentrations of HMF and furosine. Small differences were found on antioxidant capacity, although chocolate addition tended to increase the antioxidant power of products. According to our results, antioxidant capacity released after fermentation is higher, which points out to the importance of gut microbes in releasing potentially bioactive compounds. Additionally, we have found alarmingly high concentrations of furosine and HMF, which calls to research into new technologies for food processing to minimize their generation.

Relationship of Thermal Treatment and Antioxidant Capacity in Cooked Foods

Most of the foods we eat undergo a cooking process before they are eaten. During such a process, the non-enzymatic browning occurs, which generates compounds such as furosine, 5-hydroxymethylfurfural (HMF) and furfural. These are considered markers of cookedness and can therefore be used as quality indicators. In this work, we study the production of these compounds in different foods (both of plant and animal origin) that are cooked with different techniques. Additionally, we investigate correlations between the production of these markers of cookedness and the antioxidant capacity produced after in vitro digestion and fermentation. We observe that, in general, cereals and vegetables are more thermally damaged. Toasting and frying produce the highest concentrations of Maillard compounds whereas boiling the lowest. Furosine content shows a significant positive correlation with in vitro digestion data in fried foods, and with fermentation in roasted foods. Furfural content shows a significant positive correlation with in vitro digestion results in roasted foods, specifically in the Folin-Ciocalteu method.

The Gut Microbiota of Obese Children Releases Lower Antioxidant Capacity from Food than That of Lean Children

The prevalence of obesity has been increasing in children over the last few decades, becoming a concern for health professionals and governments. Gut microbial community structure in obese people have been found to differ from that of lean subjects for some taxa which could result in different production of microbial metabolites. The aim of the present work was to study whether the gut microbiota from obese children extracts a different concentration of antioxidant capacity than the gut microbiota from lean children. For this purpose, different foods were in vitro digested and in vitro fermented using fecal material from obese and lean children. FRAP, DPPH and Folin-Ciocalteu methods were used to measure the antioxidant capacity released during digestion and fermentation. Overall, when using lean gut microbiota, antioxidant capacity released was higher when measured via DPPH and FRAP. Moreover, according to DPPH results, lean gut microbiota could potentially release more antioxidant power from vegetables than from animal products, while obese gut microbiota did the opposite. On the contrary, with the FRAP method obese gut microbiota released higher levels of antioxidant power from plant products than from animal products, but the final antioxidant capacity was still lower than that released by lean gut microbiota. Therefore, these results reflect that the total antioxidant capacity of foods is influenced by the gut microbiota, although whether that antioxidant capacity is released from plant or animal products can be slightly influenced by the method used for analysis.

Development of an Unified Food Composition Database for the European Project "Stance4Health"

The European Commission funded project Stance4Health (S4H) aims to develop a complete personalised nutrition service. In order to succeed, sources of information on nutritional composition and other characteristics of foods need to be as comprehensive as possible. Food composition tables or databases (FCT/FCDB) are the most commonly used tools for this purpose. The aim of this study is to describe the harmonisation efforts carried out to obtain the Stance4Health FCDB. A total of 10 FCT/FCDB were selected from different countries and organizations. Data were classified using FoodEx2 and INFOODS tagnames to harmonise the information. Hazard analysis and critical control points analysis was applied as the quality control method. Data were processed by spreadsheets and MySQL. S4H’s FCDB is composed of 880 elements, including nutrients and bioactive compounds. A total of 2648 unified foods were used to complete the missing values of the national FCDB used. Recipes and dishes were estimated following EuroFIR standards via linked tables. S4H’s FCDB will be part of the smartphone app developed in the framework of the Stance4Health European project, which will be used in different personalized nutrition intervention studies. S4H FCDB has great perspectives, being one of the most complete in terms of number of harmonized foods, nutrients and bioactive compounds included.

Effect of roasting conditions on cocoa bioactivity and gut microbiota modulation

Cocoa is a highly consumed food with beneficial effects on human health. Cocoa roasting has an important influence on its sensory and nutritional characteristics; therefore, roasting could also play a role in cocoa bioactivity. Thus, the aim of this paper is to unravel the effect of cocoa roasting conditions on its antioxidant capacity and modifications of gut microbiota after in vitro digestion-fermentation. HMF and furfural, chemical markers of non-enzymatic browning, were analyzed in unroasted and roasted cocoa powder at different temperatures, as well as different chocolates. The antioxidant capacity decreased with roasting, most probably due to the loss of phenolic compounds during heating. In the case of the evaluated chocolates, the antioxidant capacity was 2-3 times higher in the fermented fraction. On the other hand, HMF and furfural content increased during roasting due to increasing temperatures. Moreover, unroasted and roasted cocoa powder have different effects on gut microbial communities. Roasted cocoa favored butyrate production, whereas unroasted cocoa favored acetate and propionate production in a significant manner. In addition, unroasted and roasted cocoa produced significantly different gut microbial communities in terms of composition. Although many bacteria were affected, Veillonella and Faecalibacterium were some of the most discriminant ones; whereas the former is a propionate producer, the latter is a butyrate producer that has also been linked to positive effects on the inflammatory health of the gut and the immune system. Therefore, unroasted and roasted cocoa (regardless of the roasting temperature) promote different bacteria and a different SCFA production.

Effect of Cooking Methods on the Antioxidant Capacity of Foods of Animal Origin Submitted to In Vitro Digestion-Fermentation

The human body is exposed to oxidative damage to cells and though it has some endogenous antioxidant systems, we still need to take antioxidants from our diet. The main dietary source of antioxidants is vegetables due to their content of different bioactive molecules. However, there are usually other components of the diet, such as foods of animal origin, that are not often linked to antioxidant capacity. Still, these foods are bound to exert some antioxidant capacity thanks to molecules released during gastrointestinal digestion and gut microbial fermentation. In this work, the antioxidant capacity of 11 foods of animal origin has been studied, submitted to different culinary techniques and to an in vitro digestion and gut microbial fermentation. Results have shown how dairy products potentially provide the highest antioxidant capacity, contributing to 60% of the daily antioxidant capacity intake. On the other hand, most of the antioxidant capacity was released during gut microbial fermentation (90–98% of the total antioxidant capacity). Finally, it was found that the antioxidant capacity of the studied foods was much higher than that reported by other authors. A possible explanation is that digestion–fermentation pretreatment allows for a higher extraction of antioxidant compounds and their transformation by the gut microbiota. Therefore, although foods of animal origin cannot be compared to vegetables in the concentration of antioxidant molecules, the processes of digestion and fermentation can provide some, giving animal origin food some qualities that could have been previously unappreciated.

Bioactivity of food melanoidins is mediated by gut microbiota

Melanoidins are an important component of the human diet (average consumption 10 g/day), which escape gastrointestinal digestion and are fermented by the gut microbiota. In this study melanoidins from different food sources (coffee, bread, beer, balsamic vinegar, sweet wine, biscuit, chocolate, and breakfast cereals) were submitted to an in vitro digestion and fermentation process, and their bioactivity was assessed. Some melanoidins were extensively used by gut microbes, increasing production of short chain fatty acids (mainly acetate and lactate) and favoring growth of the beneficial genera Bifidobacterium (bread crust, pilsner and black beers, chocolate and sweet wine melanoidins) and Faecalibacterium (biscuit melanoidins). Quantification of individual phenolic compounds after in vitro fermentation allowed their identification as microbial metabolites or phenolics released from the melanoidins backbone (specially pyrogallol, 2-(3,4-dihydroxyphenyl)acetic and 3-(3,4-dihydroxyphenyl)propionic acids). Our results also showed that antioxidant capacity of melanoidins is affected by gut microbiota fermentation.

Mineral profile of weight loss related foods marketed in Spain

Low calorie foods are products designed to replace complete meals or to control snacking in many hypocaloric diets. These products provide many nutrients to the human diet, but little is known about their mineral elements composition. Here we study the mineral profile of weight loss related products, including the analysis of 22 elements (As, Ba, Be, Bi, Cd, Co, Cr, Cu, K, Mn, Mo, Na, Ni, P, Pb, Th, Tl, Sb, U, V, Y and Zn) in 73 commercial products marketed in Spain. In general a portion of these products provide up to 20-30% of the daily dietary reference intake of essential trace minerals like Cr or Mo. On the contrary, some of these foods have large concentrations of toxic minerals like As, Cd or Pb. In fact, the intake of those products with higher concentrations of toxic elements during a weight loss program could pose a risk to human health.

Early and advanced stages of Maillard reaction in infant formulas: Analysis of available lysine and carboxymethyl-lysine

Although the literature on the Maillard reaction in infant formulas is extensive, most studies have focused on model systems, and in only a few cases on real food systems. Therefore, the objective of the present study was to determine the status of the Maillard reaction, both the early and advanced phases, in a variety of commercial infant formulas available on the Swedish market. Ten powder and liquid milk-based infant formulas from three manufacturers were selected to determine available lysine and CML contents, the two established indicators of the reaction. The products were also characterized with respect to protein content, carbohydrates composition, water content and water activity. In order to be able to compare the impact of different processing steps applied on powder and liquid formulas, the solid formulas contained similar ingredients as their corresponding liquid ones. Our findings showed that powder and liquid formulas contained similar available lysine concentrations regardless of the manufacturer, showing 27.14-36.57% decrease in the available lysine, compared to the reference skim milk powder in this study. The CML concentrations were in a broad range of 68.77-507.99 mg / kg protein. In the case of one manufacturer, liquid infant formulas had significantly higher CML content, compared to the powder products (p < 0.05). The results from this study are a step taken towards better understanding of the extent of the Maillard reaction in real complex systems of infant formulas.

Occurrence of Furosine and Hydroxymethylfurfural in Breakfast Cereals. Evolution of the Spanish Market from 2006 to 2018

The demand for healthier products has led the breakfast cereal sector to develop new formulations to improve the nutritional profile of breakfast cereals; however, the increase in chemical risks should also be evaluated. Amadori compounds and 5-hydroxymethylfurfural (HMF) are Maillard reaction products applied as heat damage indices in breakfast cereals. Furosine (a synthetic amino acid formed by acid hydrolysis of Amadori compounds) is linked to the loss of protein quality, while HMF has exhibited toxicological effects in cells and animals. Furosine and HMF content was evaluated in Spanish breakfast cereals whereas the effect of protein, fibre, and sugar content, the type of grain, the presence of honey, and the manufacturing process were discussed, as well as compared with a previous prospective study. The average furosine and HMF contents were 182 mg/kg and 21.7 mg/kg, respectively. Protein and fibre content were directly related to the furosine content, whereas sugar level, honey addition, and the manufacturing process affected the content of HMF. Occurrence of furosine and HMF decreased nearly 40% in a decade (2006-2018). These findings are relevant in terms of nutritional score, since lysine availability is preserved, but also from a toxicological point of view, due to the decreased daily exposure to both compounds, which dropped 30%.

Evaluation of the Availability and Antioxidant Capacity of Maillard Compounds Present in Bread Crust: Studies in Caco-2 Cells

Bread crust is one of the major contributors to the intake of Maillard reaction products (MRP). MRP improve the organoleptic properties of foods and can provide biological actions such as antioxidant properties. The transport and availability of Amadori compounds (measured as furosine) and hydroxymethylfurfural (HMF)-early and intermediary MRP-from enzymatically digested bread crust (BC) and from its soluble low-molecular weight (LMW) and high-molecular weight (HMW) fractions were investigated in the Caco-2 cell line. The absorption of the early and final MRP pool was tested by measuring the absorbance recovery (280 and 420 nm). The ability of soluble BC or its fractions to lessen the production of reactive oxygen species (ROS) was examined. Amadori compounds (furosine) were transported across Caco-2 cell monolayers from the soluble BC in percentages ranging between 40% and 56%; the lower amount of the compound supplied, the higher transport rate. However, HMF transport rate (35%) was unaffected by the initial amount of the compound. Amadori compounds and HMF contained in the LMW fraction were more efficiently transported than those present in the HMW fraction, suggesting improved absorption when supplied as free forms or linked to LMW compounds. Absorbance recovery at 280 nm was higher from the LMW fraction, whereas higher recovery was detected for the HMW fraction at 420 nm. The digested BC-but not its isolated fractions-was able to significantly reduce ROS production at basal conditions and after subjecting cells to an oxidant. A clear positive action of BC on the antioxidant defence is manifested, seemingly attributable to the combined presence of soluble LMW and HMW products.

Mitigation strategies of acrylamide, furans, heterocyclic amines and browning during the Maillard reaction in foods

The Maillard reaction (MR) occurs widely during food manufacture and storage, through controlled or uncontrolled pathways. Its consequences are ambiguous depending on the nature and processing of the food products. The MR is often used by food manufacturer to develop appealing aromas, colour or texture in food products (cereal based food, coffee, meat…). However, despite some positive aspects, the MR could decrease the nutritional value of food, generate potentially harmful compounds (e.g. acrylamide, furans, heterocyclic amines) or modify aroma or colour although it is not desired (milk, fruit juice). This paper presents a review of the different solutions available to control or moderate the MR in various food products from preventive to removal methods. A brief reminder of the role and influence of the MR on food quality and safety is also provided.

Effect of hydroxytyrosol and olive leaf extract on 1,2-dicarbonyl compounds, hydroxymethylfurfural and advanced glycation endproducts in a biscuit model

The antiglycative activity of hydroxytyrosol (HT) and olive leaf extract (OLE) was investigated in wheat-flour biscuits. Quercetin (QE) and gallic acid (GA) were used as reference of antiglycative activity of phenolic compounds. HT, OLE, QE and GA were added in the range of 0.25-0.75% (w/w). Samples were compared against a control recipe baked at 180°C/20min. HT biscuit was able to inhibit efficiently the formation of hydroxymethylfurfural (HMF) and 3-deoxyglucosone (3-DG), as well as reduced the formation of overall free fluorescent AGEs and pentosidine. The inhibition of the 3-DG and HMF formation was directly and significantly correlated under controlled baking conditions. However, samples formulated with OLE exerted similar antiglycative capacity against pentosidine and Nε-carboxyethyl-lysine, although the amount of HT in the biscuit was 100-fold lower than the biscuit formulated with HT. Methylglyoxal, 3-DG, and glyoxal were the predominant 1,2-dicarbonyl compounds after baking but only 3-DG was significantly reduced by HT.

Relationship between Glycation and Polyphenol Content and the Bioactivity of Selected Commercial Soy Milks

Soy milk is a health-promoting beverage of which consumption is steadily expanding. Different bioactivities have been associated with soy products such as antioxidant capacity, anti-inflammatory properties, or decrease of cancer development risk. These activities have been related to the presence of several compounds, including polyphenols and serine protease inhibitors, although factors influencing such activities have been scarcely studied. In this study, we have determined the antioxidant capacity (ABTS and FRAP methods measured with the global antioxidant response, GAR protocol), total phenolic content, serine protease inhibitory activity, and presence of heat damage indicators in commercial soy milks. Polyphenols were primarily responsible for the antioxidant capacity of soy milks, increasing their concentration after digestion. Glycation under heat treatment might be responsible for decreasing protease inhibitory activities in soy milks. The results obtained support a role for furosine, a known marker of Maillard reaction and glycation, as a potential indicator to monitor both thermal treatment and effects on protease inhibitory activities in soy milk. The contribution of soy milk consumption to the daily intake of antioxidants and serine protease inhibitory activities is discussed.

The Maillard reaction of a shrimp by-product protein hydrolysate: chemical changes and inhibiting effects of reactive oxygen species in human HepG2 cells

A shrimp by-product protein hydrolysate via the Maillard reaction could alleviate cellular damage, but result in higher HMF and loss of nutritional quality.

Effects of extrusion, infrared and microwave processing on Maillard reaction products and phenolic compounds in soybean

BACKGROUND

The Maillard reaction indicators furosine, hydroxymethylfurfural (HMF), acrylamide and color were determined to evaluate heat effects induced during extrusion, infrared and microwave heating of soybean. In addition, the present paper aimed to study changes in the phenolic compounds, as well as in the overall antioxidant properties of different soybean products in relation to heating at 45-140 °C during the processes.

RESULTS

Soybean proteins were highly sensible to Maillard reaction and furosine was rapidly formed under slight heating conditions during extrusion and infrared heating. Microwave heating at lower temperatures for a longer time yielded lower acrylamide levels in the final soybean products, as a result of its partial degradation. However, during infrared heating, acrylamide formation greatly increased with decreasing moisture content. After a short time of extrusion and infrared heating at 140 °C and microwave heating at 135 °C for 5 min, concentrations of HMF increased to 11.34, 26.21 and 34.97 µg g(-1), respectively.

CONCLUSION

The heating conditions caused formation of acrylamide, HMF and furosine in high concentration. The results indicate that the complex structure of soybeans provides protection of phenolic compounds from thermal degradation, and that Maillard reaction products improved the antioxidant properties of heat-treated soybean.

Effects of diets supplemented with MRPs from bread crust on the food intake and body weights in rats

Traditionally the effects of dietary Maillard reaction products (MRPs) on food intake and body weight have been described in different studies, but few investigations have been conducted to analyse the main contributors responsible. We studied the effects of long-term consumption of MRPs from bread crust (BC) on rat growth, investigating the efficiency of diet and protein utilization. Different soluble and insoluble fractions of BC were studied to analyse the possible contributors. Additionally, the colour of the faecal material and the amount of fluorescent MRPs in the urine were measured in order to demonstrate MRP excretion. Six groups of rats were fed the following diets for 88 days: control (AIN-93G diet); bread dough (BD) and BC (containing 10% of BD or BC, respectively); low and high molecular weight (LMW-HMW) (containing soluble compounds from BC with <5 kDa and >5 kDa, respectively); insoluble (containing insoluble compounds from BC). Dietary MRPs tended to reduce the food intake and body weight significantly after consumption of more complex compounds (HMW and insoluble). The L*-value in the faeces decreased in animals fed BC and its derivatives, providing evidence of the presence of MRPs. The fluorescence associated with MRP excretion in urine was higher when the LMW diet was consumed, suggesting the easier absorption and clearance of the smaller compounds of BC.

Produtos da reação de Maillard em alimentos: implicações para a saúde

A reação de Maillard é uma reação de escurecimento não enzimático que pode ocorrer em alimentos e em organismos vivos. Esta revisão tem como objetivo analisar a formação e o papel dos produtos originados a partir da reação de Maillard e seus efeitos na saúde. Para isso foram realizados levantamentos bibliográficos nas bases da área, sem restrição de data. Os resultados da revisão apontam que produtos carbonílicos inter-mediários da reação de Maillard e da peroxidação reagem facilmente com grupamentos aminas de proteínas e ácidos nucleicos, levando a modificações biológicas que podem resultar em complicações observadas no diabetes, aterosclerose e doenças neurodegenerativas. O consumo de produtos da reação de Maillard aumentou nas últimas décadas, devido ao aumento do consumo de alimentos industrializados que, em geral, sofreram processamento térmico. Essas substâncias são biodisponíveis em alguma proporção e, embora ainda não haja consenso sobre os possíveis efeitos deletérios à saúde decorrentes de sua ingestão, a comunidade científica tem expressado preocupação com as implicações em processos patológicos de que participam. Diante desses achados, ressalta-se a necessidade de estimar o consumo dos produtos da reação de Maillard, principalmente por populações vulneráveis, como crianças e diabéticos, a fim de, se necessário, estabelecer consumos diários aceitáveis e ampliar o conhecimento com vistas ao estabelecimento, no futuro, de limites para a indústria de alimentos.

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.

Kinetics of formation of three indicators of the maillard reaction in model cookies: influence of baking temperature and type of sugar

The Maillard reaction (MR), despite its impact on flavor, color, and texture of cereal products, must be controlled for possible deleterious effects on protein nutritional quality. The present study aims to simultaneously monitor three indicators of the MR reaction (acid-released lysine, furosine, and carboxymethyllysine (CML)) by GC/MS in model cookies and evaluate the effect of formulation and baking temperature. Whereas furosine followed a bell-shape kinetic, indicative of an intermediary compound, CML linearly accumulated, proving to be a good indicator of the advanced MR. Acid-released lysine continuously decreased during baking. A reference baking level was defined to compare differently processed cookies using fluorescence synchronous spectra, highly sensitive to the dough physicochemical properties. Furosine was maximal in glucose-containing cookies, but only accounted for 5-50% lysine blockage, depending on the sugar and baking temperature. High oven temperatures and the use of fructose as the sugar source were associated with lowest the lysine damage and CML formation.

Forty years of furosine – Forty years of using Maillard reaction products as indicators of the nutritional quality of foods

The Maillard reaction products (MRPs) most widely used as markers of the nutritional quality of foods are furosine, N(epsilon)-carboxymethyllysine (CML), hydroxymethylfurfural, pyrraline, pentosidine and pronyl-lysine. One of the MRPs identified first was furosine, which was quantified in foods 40 years ago as a chemical indicator of the Amadori compound N(epsilon)-fructoselysine. Since then, furosine has gained broad attention by food chemists and biomedical researchers, as its formation upon heat treatment is well characterised. Moreover, it represents the Amadori products from early Maillard reactions in which amino acids react with reducing carbohydrates, resulting in a loss of their availability. This is of importance for the essential amino acid lysine, which is also the limiting amino acid in many proteins. In order to evaluate the nutritional quality of a protein, the concomitant analysis of free - and nutritionally available - lysine and the amount of lysine reacted to form the respective MRP is essential, even for mildly processed foods. The other chemical markers of heat treatment such as CML, pyrraline, pentosidine or pronyl-lysine seem to be useful markers of the advanced stages of Maillard reactions. Compared to the conditions in which furosine is formed, these compounds are generated under more severe conditions of heat treatment. However, the concentrations analysed are significantly lower than those of furosine. Therefore, the nutritional evaluation of a food protein should include not only furosine, but also other chemical markers of heat treatment such as, for example, CML, pyrraline and pentosidine.