A.M. Pustjens

Characterisation of cell wall polysaccharides from rapeseed (Brassica napus) meal

To enable structural characteristics of individual cell wall polysaccharides from rapeseed (Brassica napus) meal (RSM) to be studied, polysaccharide fractions were sequentially extracted. Fractions were analysed for their carbohydrate (linkage) composition and polysaccharide structures were also studied by enzymatic fingerprinting. The RSM fractions analysed contained pectic polysaccharides: homogalacturonan in which 60% of the galacturonic acid residues are methyl-esterified, arabinan branched at the O-2 position and arabinogalactan mainly type II. This differs from characteristics previously reported for Brassica campestris meal, another rapeseed cultivar. Also, in the alkali extracts hemicelluloses were analysed as xyloglucan both of the XXGG- and XXXG-type decorated with galactosyl, fucosyl and arabinosyl residues, and as xylan with O-methyl-uronic acid attached. The final residue after extraction still contained xyloglucan and remaining (pectic) polysaccharides next to cellulose, showing that the cell wall matrix of RSM is very strongly interconnected.

Effects of processing technologies and pectolytic enzymes on degradability of nonstarch polysaccharides from rapeseed meal in broilers

Rapeseed meal (RSM) contains a high level of nonstarch polysaccharides (NSP) that are not well degraded in poultry and interfere with digestion of other nutrients as protein, starch, and fat. By altering physicochemical properties of NSP from RSM, processing and enzyme technologies might improve digestive utilization of RSM, enhancing its potential as a source of nutrients in poultry diets. The effects of wet milling and extrusion in combination with pectolytic enzymes on the degradability of RSM in broilers were investigated in a 3 × 2 factorial arrangement. Wet milling and extrusion did not affect total tract apparent digestibility of DM, CP, crude fat, and nonglucose polysaccharides (NGP). Addition of pectolytic enzymes did not affect total tract apparent digestibility of CP and crude fat, but improved degradability of NGP by 9 to 20% units (P < 0.001), independent of prior technological processing of RSM. This coincided with an increased NGP concentration in the ceca (4 to 7 g/g of cobalt, P < 0.001), indicating that more NGP were solubilized such that they could enter the ceca and become available for fermentation. Particle size reduction facilitated solubilization of polysaccharides from RSM, increasing the concentration of NGP found in the ceca (4 g/g of cobalt, P = 0.008). Without help of additional pectolytic enzymes, those solubilized structures could, however, still not be degraded by the cecal microbiota. Feed intake, BW gain, and feed conversion ratio were not affected. No interaction between processing technologies and enzyme addition was found. Apparently, the processing technologies studied were not facilitating accessibility of NSP to pectolytic enzymes added to the feed in vivo.

Processing technologies and cell wall degrading enzymes to improve nutritional value of dried distillers grain with solubles for animal feed: an in vitro digestion study.

Currently, the use of maize dried distillers grain with solubles (DDGS) as protein source in animal feed is limited by the inferior protein quality and high levels of non-starch polysaccharides (NSP). Processing technologies and enzymes that increase NSP degradability might improve digestive utilization of DDGS, enhancing its potential as a source of nutrients for animals. The effects of various combinations of processing technologies and commercial enzyme mixtures on in vitro digestion and subsequent fermentation of DDGS were tested. Wet-milling, extrusion, and mild hydrothermal acid treatment increased in vitro protein digestion but had no effect on NSP. Severe hydrothermal acid treatments, however, effectively solubilized NSP (48-78%). Addition of enzymes did not affect NSP solubilization in unprocessed or processed DDGS. Although the cell wall structure of DDGS seems to be resistant to most milder processing technologies, in vitro digestion of DDGS can be effectively increased by severe hydrothermal acid treatments.

Food Fraud and Authenticity : Emerging issues and future trends

Abstract Food fraud is a significant and growing problem, driven by globalization, economic opportunity, and the low probability and severity of punishment. Although food fraud is economically motivated, it may result in serious health consequences. Therefore, emerging food fraud issues are described in this chapter, including the usage of food fraud databases. Analytical verification of food fraud and food authentication is needed to support proper food safety management systems. However, due to time and money constraints, only a restricted number of samples can be analyzed in a laboratory. For analysis outside the laboratory, rapid, nondestructive, nontargeted methods are needed. This can be either handheld equipment for food safety inspectors or in-line equipment for the food manufacturers.

Effects of acid extrusion on the degradability of maize distillers dried grain with solubles in pigs.

Commonly used feed processing technologies are not sufficient to affect recalcitrant nonstarch polysaccharides (NSP) such as arabinoxylans present in maize distillers dried grain with solubles (DDGS). Instead, hydrothermal treatments combined with acid catalysts might be more effective to modify these NSP. The objective of this experiment was to investigate the effects of hydrothermal maleic acid treatment (acid extrusion) on the degradability of maize DDGS in growing pigs. It was hypothesized that acid extrusion modifies DDGS cell wall architecture and thereby increases fermentability of NSP. Two diets, containing either 40% (wt/wt) unprocessed or acid-extruded DDGS, were restrictedly fed to groups of gilts (n=11, with 4 pigs per group; initial mean BW: 20.8±0.2 kg) for 18 d and performance and digestibility were analyzed. Acid extrusion tended to decrease apparent ileal digestibility (AID) of CP (approximately 3 percentage units [% units]); P=0.063) and starch (approximately 1% unit; P=0.096). Apparent digestibility of CP and starch measured at the mid colon (2% units, P=0.030, for CP and 0.3% units, P<0.01, for starch) and apparent total tract digestibility (ATTD; 3% units, P<0.01, for CP and 0.2% units, P=0.024, for starch) were lower for the acid-extruded diet compared with the control diet. Hindgut disappearance was, however, not different between diets, indicating that reduced CP and starch digestibility were mainly due to decreased AID. Acid extrusion tended to increase AID of NSP (6% units; P=0.092) and increased digestibility of NSP measured at the mid colon (6% units; P<0.01), whereas hindgut disappearance and ATTD of NSP did not differ between diets. Greater NSP digestibility was mainly due to greater digestibility of arabinosyl, xylosyl, and glucosyl residues, indicating that both arabinoxylan and cellulose degradability were affected by acid extrusion. In conclusion, these results show that acid extrusion did not improve degradation of DDGS for growing pigs. Although acid extrusion seemed to facilitate more rapid degradation of NSP and shifted fermentation to more proximal gastrointestinal segments, total extent of NSP degradation was not affected. More than 35% of the NSP from DDGS remained undegraded, independent of technological processing. Enzyme technologies that specifically target ester-linked acetyl, feroloyl, or coumaroyl groups were identified to be of interest for future research.

Separation of digesta fractions complicates estimation of ileal digestibility using marker methods with Cr2O3 and cobalt-ethylenediamine tetraacetic acid in broiler chickens

Marker methodologies to measure ileal and total tract digestibilities of diets varying in content and degradability of dietary fiber in broiler chickens were evaluated. Chromium sesquioxide (Cr2O3) and cobalt-ethylenediamine tetraacetic acid (Co-EDTA) were used as markers of solid and soluble fractions, respectively, and compared with digestibility values obtained with the total collection method. Groups of broilers (n = 17, 11 broilers/group) were assigned to a low-fiber diet or 1 of 2 high-fiber diets, the latter 2 containing 35% rapeseed meal (RSM). Pectolytic enzymes were added to one RSM diet to improve degradability of the fiber fraction. Excreta were quantitatively collected for 96 h, and contents from ileum and ceca were collected at slaughter at 29, 30, or 31 d of age. Chromium recovery in excreta ranged between 86 and 95%, whereas cobalt recovery was considerably lower (66 to 70%). Chromium:cobalt ratio was higher in ileal digesta than in feed. Hardly any chromium was found in the ceca, indicating that separation of the marker and specific digesta fractions occurs. Estimates of apparent total tract digestibility (ATTD) were lower when calculated using the marker method compared with the total collection method, particularly in high-fiber diets. Using Cr2O3 as a marker, differences were relatively small and effects due to enzyme addition were generally similar. Using Co-EDTA as a marker, ATTD of all components were lower compared with values obtained using the collection method (3 to 45 percentage units, P < 0.001), likely related to the low Co recovery. When estimating apparent ileal digestibility (AID), separation of marker and digesta resulted in unrealistically high estimates for the digestibility of nonglucose polysaccharides (54 to 66%), exceeding ATTD values by 16 to 42 percentage units. Moreover, the effect of pectolytic enzyme addition on the AID of nonglucose polysaccharides was in the opposite direction when compared with total collection. The data illustrate that fractionation of digesta, particularly in high-fiber diets, complicates accurate AID measurements in broilers, regardless of the choice of markers used.

Characterization of Retail Conventional, Organic, and Grass Full-Fat Butters by Their Fat Contents, Free Fatty Acid Contents, and Triglyceride and Fatty Acid Profiling

In the Netherlands, butter is produced from milk originating from three different production systems: conventional, organic, and grass-fed cows. The aim of the current study was to characterize these types of butters, and pinpoint distinct compositional differences. Retail conventional (n = 28), organic (n = 14), and grass (n = 12) full-fat butters were collected during the winter and summer seasons. Samples were analyzed for their fat content, free fatty acid (FFA) content, and triglyceride (TG) and fatty acid (FA) profiles. The fat content was significantly lower in conventional butters than in organic butters and the FFA content was significantly lower in conventional butters compared with grass butters. Also, organic butters differed significantly from their conventional counterparts with regard to their TG and FA profiles. The TG profiles of the organic and grass butters did not differ significantly. The FA profiles of grass butters were less distinct, since only a few FAs differed significantly from conventional (six FAs) and organic (eight FAs) butters.

Understanding carbohydrate structures fermented or resistant to fermentation in broilers fed rapeseed (Brassica napus) meal to evaluate the effect of acid treatment and enzyme addition

Unprocessed and acid-extruded rapeseed meal (RSM) was fed to broiler chickens, with and without addition of commercial pectolytic enzymes. Nonstarch polysaccharide (NSP) fermentability and unfermented NSP structures from RSM were studied in the excreta in detail. From unprocessed RSM, 24% of the nonglucose polysaccharides could be fermented. Acid treatment did not have a significant effect, but enzyme addition did improve fermentability to 38%. Most likely, the significant increase in NSP fermentability can be ascribed to the addition of pectolytic enzymes, which decreased branchiness of the water-soluble arabinan. Mainly xyloglucan, (glucurono-)xylan, (branched) arabinan, and cellulose remained in the excreta. The proportion of unextractable carbohydrates increased in excreta from broilers fed acid-extruded RSM. Probably, acid extrusion resulted in a less accessible NSP matrix, also decreasing the accessibility for pectolytic enzymes added in the diet. During alkaline extraction of the excreta, 39 to 52% (wt/wt) of the insoluble carbohydrates was released as glucosyl- and uronyl-rich carbohydrates, probably originally present via ester linkages or hydrogen bonding within the cellulose-lignin network. These linkages are expected to hinder complete NSP fermentation and indicate that digestibility of RSM may benefit substantially from an alkaline treatment or addition of esterases.

Effects of processing technologies combined with cell wall degrading enzymes on in vitro degradability of barley

Effects of processing technologies and cell wall degrading enzymes on in vitro degradation of barley were tested in a 5 × 2 factorial arrangement: 5 technologies (unprocessed, wet-milling, extrusion, autoclaving, and acid-autoclaving), with or without enzymes. Upper gastrointestinal tract digestion (Boisen incubation) and large intestinal fermentation (gas production technique) were simulated in duplicate. All technologies increased digestion of DM (13 to 43% units) and starch (22 to 51% units) during Boisen incubation, compared with the unprocessed control (P < 0.01). Wet-milling, extrusion, and acid-autoclaving increased CP digestion by 29 to 33% units (P < 0.01). Xylanase and β-glucanase addition increased digestion of DM (≈ 20% units), starch (≈ 20% units), and CP (≈ 10% units) in unprocessed and autoclaved barley (P < 0.01). Wet-milling, extrusion, and acid-autoclaving, reduced the extent (50%) and maximum rate (60 to 75%) of fermentation (P < 0.01), which appeared to reflect the reduced amount of starch present in the Boisen residues. In conclusion, wet-milling, extrusion, and acid-autoclaving improved in vitro starch and CP digestion in barley, which is related to the cell wall matrix disruption. Addition of xylanases and β-glucanases improved in vitro starch and CP digestion only in unprocessed barley or barley poorly affected by processing.

Advances in Authenticity Testing of Geographical Origin of Food Products

Abstract Ongoing consumer demands and greater labeling specifications regarding the geographical origin of foods have driven advanced research efforts using existing and new technologies in the last decade in this area of interest. In this chapter, an update is provided on state-of-the-art equipment and research on confirming the provenance of foods by a range of analytical means. Recent advances in isotopic and atomic analysis, compositional analysis using separation techniques, and (semi-)nondestructive techniques are discussed. Most often, the data produced require advanced statistical methods in order to extract the origin-related analytical properties and to allow eventual assessment of the food products origin.