Extent of thermal decomposition of indole glucosinolates during the processing of canola seed

Chemical composition and digestible and metabolizable energy contents in cold-pressed canola expellers fed to growing pigs

Cold-pressed canola expellers (CPCE) are a byproduct of canola oil production obtained using the pressing method without thermal and chemical treatment. While CPCE is a valuable source of dietary energy and protein in swine nutrition, the discrepancy in processing conditions leads to variability in the nutritional quality of CPCE from different sources. This study aimed to determine the chemical composition, and digestible energy (DE) and metabolizable energy (ME) values of CPCE when fed to growing pigs. Samples of CPCE were collected from five processing facilities across Western Canada. The physical appearance of the CPCE samples hinted at a potential quality variation. Samples were subjected to a complete chemical characterization. Variations (P < 0.05) were observed in the chemical composition, with the exception of non-phytate phosphorus, xylose, mannose, and galactose. On a g/kg dry matter (DM) basis, CPCE samples ranged as follows: ether extract from 85 to 177; crude protein (CP) from 351 to 419; neutral detergent fiber 231 to 300; total dietary fiber from 326 to 373; glycoproteins from 30 to 76; non-starch polysaccharides from 188 to 204, non-phytate phosphorus from 5.5 to 6.4, and gross energy (GE) in kcal/kg 5,027 to 5,635. The total glucosinolates (GLS) ranged from 5.0 to 9.7 µmol/g DM. Thirty-six (36) growing barrows, with an average initial body weight of 19.2 ± 1.0 kg, were individually housed in metabolism crates and assigned to one of the six experimental diets in a completely randomized design, with six pigs per diet. The diets included a corn-soybean meal (SBM)-based basal diet (100%) and five (5) experimental diets in which 18% of the basal diet was substituted with CPCE from different producers. Pigs were fed the experimental diets for 10 d, with 5-d adaptation period, followed by a 5-d period for the total, but separate, collection of feces and urine. Significant differences (P < 0.05) among processing plants were observed in the DE and ME contents of CPCE, which averaged 3,531 and 3,172 kcal/kg DM, respectively. Differences (P < 0.05) were noted in the apparent total tract digestibility of GE, nitrogen (N), as well as in the retention of DM, GE, and N in CPCE samples. In conclusion, while the chemical composition and values of DE and ME in CPCE vary among processors, the byproduct obtained through cold pressing process can be a valuable source of energy and protein for pig nutrition.

Biotransformation technology and high-value application of rapeseed meal: a review

Rapeseed meal (RSM) is an agro-industrial residue of increased functional biological value that contains high-quality proteins for animal feed. Due to the presence of antinutritional factors and immature development technology, RSM is currently used as a limited feed additive and in other relatively low-value applications. With increasing emphasis on green and sustainable industrial development and the added value of agro-industrial residues, considerable attention has been directed to the removal of antinutritional factors from RSM using high-efficiency, environment-friendly, and cost-effective biotechnology. Similarly, the high-value biotransformations of RSM have been the focus of research programmes to improve utilization rate. In this review, we introduce the sources, the nutrient and antinutrient content of RSM, and emphasize improvements on RSM feed quality using biological methods and its biotransformation applications.

Piglet performance and physiological effects linked to reduced glucosinolate transformations in feed products based on rapeseed pressed cakes

The nutritional quality of rapeseed press cakes (RPCs) in piglet feed is closely linked to its digestibility and the content of glucosinolates. This study investigates the significance of intact glucosinolate (glc) levels and degree of glc transformations on piglets performance. Four different RPCs were made from a low glc (11 µmol/g seed DM) containing B. napus L. seed variety Lioness (RPC-LW, RPC-LXW, RPC-LC, RPC-LCD). RPC made from the variety Excalibur containing the upper level of glc (24 µmol/g seed DM) of double rapeseed and produced at higher and prolonged temperature (RPC-UXW) served as negative control, while soya bean protein concentrate served as positive control. Piglets (8 kg) were fed ad libitum diets balanced for RPC protein content, with RPC inclusion of 84-98 g/kg (day 0-14) and 151-178 g/kg (day 15-50). Glc transformation was reduced from 42% to 24% (7.3-4.2 µmol/g RPC) when the temperature input was lowered in the warm pressing of oil, while the glc loss was less pronounced (17%) when cold pressing was applied. The following feed pelleting process further reduced Glc concentration from 11% to 40% in warm-pressed RPCs and 54 to 85% in cold-pressed RPCs. The RPC products replaced soya bean protein without any negative effects on performance, except for piglets served cold-pressed RPC, which had a reduction in average daily weight gain (ADG) (5%-7%, p < 0.05, Day 15-50). RPC in the feed led to increased liver weight in all piglets (p = 0.026). This may point at long-term effects from feeding with RPC. Intestinal absorption of intact glcs was proven by their detection in urine. In conclusion, warm-pressed RPC can be used as feed for piglet, while the presence of active myrosinase may have a negative effect on performance and cakes should either be included in lower amounts than used in the present study (18%) or include myrosinase inactivation before use.

Indole-3-carbinol: a plant hormone combatting cancer

A diet rich in cruciferous vegetables such as cauliflower, broccoli, and cabbage has long been considered healthy, and various epidemiological studies suggest that the consumption of cruciferous vegetables contributes to a cancer-protecting diet. While these vegetables contain a vast array of phytochemicals, the mechanism by which these vegetables counteract cancer is still largely unresolved. Numerous in situ studies have implicated indole-3-carbinol, a breakdown product of the glucosinolate indole-3-ylmethylglucosinolate, as one of the phytochemicals with anti-cancer properties. Indole-3-carbinol influences a range of cellular processes, but the mechanisms by which it acts on cancer cells are slowly being revealed. Recent studies on the role of indole-3-carbinol in Arabidopsis opens the door for cross-kingdom comparisons that can help in understanding the roles of this important phytohormone in both plant biology and combatting cancer.

Effect of the desolventizing/toasting process on chemical composition and protein quality of rapeseed meal

Background

During processing in a desolventizer/toaster (DT), rapeseed meal (RSM) is heated to evaporate the hexane and to reduce the level of heat-labile anti-nutritional factors such as glucosinolates (GSL). However, excessive heat treatment may reduce amino acid (AA) content in addition to lower AA digestibility and availability in RSM. The objective of the present study was to produce from one batch of a 00-rapeseed variety (17 μmol GSL/g dry matter (DM), seed grade quality) five differently processed RSM under standardized and defined conditions in a pilot plant, and to determine the impact of these different treatments on protein solubility and chemical composition, in particular with regard to contents of AA including reactive Lys (rLys) and levels of total and individual GSL.

Methods

Four RSM were exposed to wet toasting conditions (WetTC) with increasing residence time in the DT of 48, 64, 76, and 93 min. A blend of these four RSM was further processed, starting with saturated steam processing (< 100 °C) and followed by exposure to dry toasting conditions (DryTC) to further reduce the GSL content in this RSM.

Results

The contents of neutral detergent fiber and neutral detergent fiber bound crude protein (CP) increased linearly (P < 0.05), as residence time of RSM in the DT increased from 48 to 93 min, whereas contents of total and most individual GSL and those of Lys, rLys, Cys, and the calculated ratio of Lys:CP and rLys:CP decreased linearly (P ≤ 0.05). The combination of wet heating and DryTC resulted in the lowest GSL content compared to RSM produced under WetTC, but was associated with lowest protein solubility.

Conclusions

It can be concluded that by increasing residence time in the DT or using alternative processing conditions such as wet heating combined with DryTC, contents of total and individual GSL in RSM can be substantially reduced. Further in vivo studies are warranted to elucidate if and to which extent the observed differences in protein quality and GSL content between RSM may affect digestibility and bioavailability of AA in monogastric animals.

Effect of microwave treatment on the efficacy of expeller pressing of Brassica napus rapeseed and Brassica juncea mustard seeds

A study was conducted to evaluate the effect of microwave heating on the efficacy of expeller pressing of rapeseed and mustard seed and the composition of expeller meals in two types of Brassica napus rapeseed (intermediate- and low-glucosinolate) and in Brassica juncea mustard (high-glucosinolate). Following microwave treatment, the microstructure of rapeseed using transmission electron microscopy showed a significant disappearance of oil bodies and myrosin cells. After 6 min of microwave heating (400 g, 800 W), the oil content of rapeseed expeller meal decreased from 44.9 to 13.5% for intermediate-glucosinolate B. napus rapeseed, from 42.6 to 11.3% for low-glucosinolate B. napus rapeseed, and from 44.4 to 14.1% for B. juncea mustard. The latter values were much lower than the oil contents of the corresponding expeller meals derived from the unheated seeds (i.e., 26.6, 22.6, and 29.8%, respectively). Neutral detergent fiber (NDF) contents showed no differences except for the expeller meal from the intermediate-glucosinolate B. napus rapeseed, which increased from 22.7 to 29.2% after 6 min of microwave heating. Microwave treatment for 4 and 5 min effectively inactivated myrosinase enzyme of intermediate-glucosinolate B. napus rapeseed and B. juncea mustard seed, respectively. In low-glucosinolate B. napus rapeseed the enzyme appeared to be more heat stable, with some activity being present after 6 min of microwave heating. Myrosinase enzyme inactivation had a profound effect on the glucosinolate content of expeller meals and prevented their hydrolysis to toxic breakdown products during the expelling process. It appeared evident from this study that microwave heating for 6 min was an effective method of producing expeller meal without toxic glucosinolate breakdown products while at the same time facilitating high yield of oil during the expelling process.

Simultaneous quantification of sinigrin, sinalbin, and anionic glucosinolate hydrolysis products in Brassica juncea and Sinapis alba seed extracts using ion chromatography

Although mustards such as Sinapis alba and Brassica juncea contain glucosinolates (sinalbin and sinigrin, respectively) that hydrolyze to form biopesticidal products, routine quality control methods to measure active ingredients in seed and seed meals are lacking. We present a simple and fast ion chromatography method for the simultaneous quantification of sinigrin, sinalbin, and anionic hydrolysis products in mustard seed to assess biological potency. Optimum conditions include isocratic elution with 100 mM NaOH at a flow rate of 0.9 mL/min on a 4 × 210 mm hydroxide-selective anion-exchange column. All anion analytes including sinigrin, sinalbin, SO4(2-), and SCN(-) yielded recoveries ranging from 83 to 102% and limits of detection ≤0.04 mM, with samples displaying little interference from plant matrix components. Sample preparation is minimized and analysis times are shortened to <90 min as compared with previous methods that took days and multiple instruments.

Reactivity and stability of glucosinolates and their breakdown products in foods

The chemistry of glucosinolates and their behavior during food processing is very complex. Their instability leads to the formation of a bunch of breakdown and reaction products that are very often reactive themselves. Although excessive consumption of cabbage varieties has been thought for long time to have adverse, especially goitrogenic effects, nowadays, epidemiologic studies provide data that there might be beneficial health effects as well. Especially Brassica vegetables, such as broccoli, radish, or cabbage, are rich in these interesting plant metabolites. However, information on the bioactivity of glucosinolates is only valuable when one knows which compounds are formed during processing and subsequent consumption. This review provides a comprehensive, in-depth overview on the chemical reactivity of different glucosinolates and breakdown products thereof during food preparation.

Factors that affect the nutritive value of canola meal for poultry

This article reviews the factors affecting the nutritive value of canola meal (CM), including glucosinolates, sinapine, phytic acid, tannins, dietary fiber, and electrolyte balance. It also addresses the means of improving the nutritive value of CM throughout seed dehulling, development of low-fiber canola, or application of feed enzymes. Over the years, the glucosinolate content of canola has been declining steadily and is now only about one-twelfth of that of the older high-glucosinolate rapeseed (that is, 10 vs. 120 μmol/g). Therefore, the rations for broilers or laying hens could now contain 20% of CM without producing any adverse effects. Tannins are of lesser importance due to their presence in the hull fraction and thus low water solubility. Sinapine has been implicated with the production of a "fishy" taint in brown-shelled eggs, which results from a genetic defect among the strain of Rhode Island Red laying hens. The White Leghorns have been reported not to be affected. Although lower in protein, CM compares favorably with soybean meal with regard to amino acid content. Because CM contains more methionine and cysteine but less lysine, both meals tend to complement each other when used together in poultry diets. Canola meal is low in arginine (Arg) which could be of importance when introducing CM to broiler diets at high inclusion rates. The Arg content of CM is approximately two-thirds of that of soybean meal. Chickens fail to synthesize Arg and are highly dependent on dietary sources for this amino acid. Supplementation of Arg to CM-based diets has been shown to partly restore the growth performance. Dietary cation-anion difference in CM is also less than optimal due to the high sulfur and low potassium contents. Seed dehulling has not been very successful due to excessive fineness and thus difficulties with percolation of the miscella through the cake. Development of low-fiber, yellow-seeded canola and the use of enzymes have proven to increase the energy utilization and the nutritive value of CM for poultry.