Studies on methodology in dietary fibre analysis : a neutral detergent fibre method using glucoamylase : a thesis presented in partial fulfilment of the requirements for the degree of Master of Philosophy in Food Technology at Massey University

The dietary fibre content of foods is conveniently and rapidly determined by the neutral and acid detergent methods devised originally by Van Soest and associates. A serious disadvantage of the neutral detergent method relates to the interference caused by starch during filtration when the method is applied to cereals and cereal products. In these circumstances the results of neutral detergent fibre (NDF) measurements are variable and often over-estimated . A study of the starch-lipid reaction which takes place when cereal products are heated in Van Soest's neutral detergent solution showed that although the precipitate derived from pure wheat starch and lipid is soluble in hot water this action is often far from complete when much fibrous cereal matter is present. Much of the starch appears to be occluded in the NDF residue which then takes on a gummy-like character and tends to clog the filter. Southgate recently recommended purified amyloglucosidase from Aspergillus niger (Boehringer) for the purpose of hydrolysing starch in cereal samples before starting the neutral detergent extraction. Present studies have been concerned with the development of this enzymatic procedure with the aim of devising improved methodology and enhancing existing knowledge of the behavioural characteristics of amyloglucosidases from A. niger and from an alternative source, Rhizopus spp. Preliminary investigations showed that amyloglucosidase from A. niger (Boehringer) was completely effective as a starch hydrolysing agent in the pretreatment of a cereal substrate but that in order to use the enzyme economically it was necessary to use a semi micro version of Van Soest's neutral detergent extraction procedure. The main features of the new method are as follows: preparation of a subsample of lipid-free food sample of fine particle size; gelatinization of starch before enzyme treatment; treatment with the minimum quantity of enzyme (2 mg); extraction with neutral detergent at half the normal rate; separation of detergent solution from the residue by means of centrifugation; dehydration of the residue with acetone before filtration; special techniques for filtration, drying and weighing procedures. A table of NDF values for various cereal products determined by the semi micro procedure is presented. The results agree, for the most part, with the results of other workers in this field, the exceptions being for cornflakes, rolled oats and puffed wheat. The coefficients of variation for the NDF values compare favourably with those of other workers. A semi micro version of Van Soest's acid detergent method of evaluating dietary fibre was devised and is described with supporting analytical data. Tests performed with a low cost preparation of amyloglucosidase from Rhizopus spp (Sigma) showed that the crude enzyme was capable of fully hydrolysing the starch component of cereal products before commencing the neutral detergent extraction procedure but that it also seriously reduced the NDF values. In order to establish the cause of the discrepancies two approaches were made: an attempt was made to analyse the products of enzymatic hydrolysis; and a study of the effect of enzyme concentration on the yield of neutral detergent fibre was undertaken. The former approach proved impracticable, the latter suggested that either impurities in the crude enzyme preparation were responsible or the amyloglucosidase itself was active towards one or more components of dietary fibre. In order to determine which of the alternative explanations was correct small amounts of the crude enzyme preparation were purified by means of anion exchange chromatography using DEAE cellulose and one of two buffer systems, one based on citrate-phosphate, the other on tris-HCl. The citrate-phosphate conditions reported by Pazur and Lineback et al for the column separation of amyloglucosidase of A. niger were found to be quite unsuitable for the enzyme from Rhizopus spp. and a new set of conditions had to be determined for this enzyme. The activity of small amounts of the purified enzyme (< 1mg) was estimated by an improvised visual method using buffered 1% wheat starch, and the effect of the enzyme on cereal fibre was determined by means of the semi micro neutral detergent procedure using 0.08-0.2 g wholemeal flour as a substrate. It was found that both crude and purified forms of the enzyme caused a loss of ca 30% NDF from wholemeal flour, from which it was concluded that amyloglucosidase from Rhizopus spp was not a suitable enzyme for use in the neutral detergent method of measuring fibre. A literature review of the known chemistry of the amyloglucosidases of A. niger and R. delemar showed that differences in molecular structure reported by Pazur and others could account for their different electrophoretic properties. In the light of the present work it appears that another important biochemical difference between these enzymes relates to the activity of the Rhizopus enzyme towards the dietary fibre component of cereals

Chemo-enzymatic saccharification strategy of microalgae chlorella sorokiniana

Biofuel production using microalgae attracted much attention because it can be cultured using CO2 and sunlight. With high carbohydrate content, microalgae have the potential to be used as a fermentation feedstock for bioethanol production. In present work, chemo-enzymatic saccharification of Chlorella sorokiniana microalgae were investigated. Chemical hydrolysis of the biomass followed by enzymatic hydrolysis and was also evaluated the effect of combining the two enzymes and the sequential addition. The effect of α-amylase concentrations was analyzed in ranged between 50 and 8000 U/g of biomass and for amyloglucosidase between 90 and 600 U/g of biomass. The higher concentrations showed the highest conversion of reducing sugars. The α-amylase concentration 8000 U/g of biomass presented a conversion of 43.06 ± 2.92% (w/w), while amyloglucosidase with 600 U/g of biomass obtained 76.57 ± 6.42% (w/w). The combination of two enzymes simultaneously was more efficient than the sequential addition for low enzyme concentrations (α-amylase 50 U/g and amyloglucosidase 90 U/g) with a total reducing sugar of 22.78 ± 3.06 and 16.92 ± 2.06% (w/w), respectively. On the other hand, using the higher enzymes concentrations, no difference was observed between the two addition strategies, 58.9 ± 3.55 and 57.05 ± 2.33% (w/w) for the sequential and simultaneous, respectively. Both strategies didn’t present advantage, since the amyloglucosidase enzyme alone produced slightly higher results. Even thought, the obtained results showed successfully performed saccharification of microalgal biomass and clearly point to microalgae use for saccharification and subsequent bioethanol production.Part of this work has been supported by European governments (INTERREG VA-POCTEP- 2014-2020; 0055_ALGARED_PLUS_5_E) and the Portuguese Science Foundation (FCT) through the grant UID/MAR/00350/2013 to the CIMA of the University of Algarve.info:eu-repo/semantics/publishedVersio

Development of methods for capillary isoelectric focusing of dairy proteins : a thesis presented in partial fulfilment of the requirements for the degree of Master of Science in Chemistry at Massey University

Capillary Isoelectric Focusing (CIEF) is a high-resolution technique which can be applied to the separation and characterisation of complex biological mixtures such as dairy proteins. Although dairy proteins are commonly analysed by traditional gel electrophoresis techniques including 2-Dimensional PAGE, CIEF offers the advantages of reduced analysis times, the ability to handle smaller sample volumes and increased sensitivity with improved separation efficiencies. Several methods for capillary isoelectric focusing of dairy proteins have been developed herein. For the analysis of soluble whey proteins methods that can be used with either UV or mass spectrometry (MS) detection have been set up. For MS detection a coaxial sheath flow interface in conjunction with electrospray ionisation has been utilised. For analysis of the inherently insoluble casein proteins with UV detection denaturing and reducing agents have been introduced into the system. Results have shown very close similarities to those obtained by IEF gels

Novel pyrrolizidine alkaloid

The present invention involves a purified bioactive compound of the formula: ##STR1## wherein at least one of R.sub.1, R.sub.2, R.sub.3 and R.sub.4 are H or an acyl having less than about five carbon atoms. More specifically the preferred purified bioactive compound is (1R, 1R, 3R, 7S, 7aR)-3-hydroxymethyl-1,2,7-trihydroxypyrrolizidine.Board of Regents, University of Texas Syste

Nutritional characterization of gluten free non-traditional pasta

When a food is formulated, its characterization is important from the chemical and biochemical point of view; even more whennon-traditional raw materials are used. Noodles were made with cassava starch and corn flour (4:1), milk, egg, salt and xanthangum. The chemical composition of the pasta was determined and the total and resistant starch content was quantified. Thehydrolysis rate of the starch was measured at different times, from which the hydrolysis index and, subsequently, the predictiveglycemic index was calculated. The chemical composition of the noodles showed its high content of total fibers. From thedigestibility tests, high values were obtained for proteins (93%), and average values for the starch (52%). The results of the starchhydrolysis kinetics showed a higher proportion of slowly digestible starch with a low glycemic index (46%). Analyzed noodles arewithin the dietary guidelines that suggest a diet with high total dietary fiber content and low glycemic index.Fil: Milde, Laura Beatríz. Universidad Nacional de Misiones. Facultad de Ciencias Exactas, Químicas y Naturales; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Nordeste; ArgentinaFil: Chigal, Paola Soledad. Universidad Nacional de Misiones. Facultad de Ciencias Exactas, Químicas y Naturales; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Nordeste; ArgentinaFil: Chiola Zayas, Maria Ofelia. Universidad Nacional de Misiones. Facultad de Ciencias Exactas, Químicas y Naturales; Argentin

Comparasion of iles-iles and cassava tubers as a Saccharomyces cerevisiae substrate fermentation for bioethanol production

Produksi bioetanol meningkat dengan cepat karena merupakan energi terbarukan untuk mengatasi krisis energi yang disebabkan oleh habisnya minyak fosil. Produksi bioetanol skala besar di industri umumnya menggunakan bahan baku seperti tebu, jagung, dan ubi kayu yang juga diperlukan sebagai sumber makanan. Oleh karena itu, banyak studi pada proses bioetanol terkait dengan penggunaan bahan baku yang tidak bersaing dengan pasokan makanan. Salah satu alternatif bahan baku dapat dimanfaatkan untuk produksi bioetanol adalah bahan berpati yang tersedia secara lokal yaitu iles-iles (Amorphophallus mueller Blum). Kandungan karbohidrat umbi iles-iles sekitar 71,12% yang sedikit lebih rendah dibandingkan dengan umbi singkong (83,47%). Pengaruh berbagai bahan awal, konsentrasi pati, pH, waktu fermentasi dipelajari. Konversi dari bahan berpati menjadi etanol memiliki tiga langkah, pencairan dan sakarifikasi dilakukan dengan α-amilase dan amyloglucosidase kemudian difermentasi dengan ragi S.cerevisiaie. Bioetanol tertinggi diperoleh pada variabel berikut rasio pati: air = 1:4; likuifaksi dengan 0,40 mL α-amilase (4h); sakarifikasi dengan amyloglucosidase 0,40 mL (40h); fermentasi dengan 10 mL S.cerevisiae (72h) memproduksi bioetanol 69,81 g/L dari singkong sementara 53,49 g/L dari umbi iles-iles. Pada kondisi optimum, gula total dihasilkan 33.431 g/L dari ubi kayu sementara 16.175 g/L dari umbi iles-iles. Pengaruh pH menunjukkan bahwa etanol yang dihasilkan terbaik diperoleh pada pH fermentasi 5,5 baik untuk ubi kayu maupun umbi iles-iles. Hasil studi menunjukkan bahwa umbi iles-iles menjanjikan sebagai bahan baku bioetanol karena menghasilkan bioetanol hampir sama dengan ubi kayu. Key words: singkong, iles-iles, etanol, energi alternatif

Physicochemical modification of native and extruded wheat flours by enzymatic amylolysis

Producción CientíficaEnzymatic hydrolysis could be an alternative way to modify flour functionality. The effect of two different enzymes, α-amylase and amyloglucosidase, and their combination on microstructure, oligosaccharide content, crystalline order, pasting, gel hydration, and colour properties of native and extruded wheat flours was investigated. Micrographs showed different mechanisms of actuation of the different enzymes on native and extruded flours, achieving greater than 300% and 500% increases of glucose and maltose contents, respectively, in extruded flours compared with their native counterparts. Native flours displayed higher values of water absorption capacity and swelling power than extruded flours. Flours treated by a combination of amylase and amyloglucosidase showed low swelling power. Regarding colour, native flours were darker and more reddish than extruded flours, whereas flours treated by amyloglucosidase, and therefore had a higher glucose content, were darker and more reddish

A note on the effect of the composition of barley produced at different locations on performance of growing pigs.

peer-reviewedLocation of production has been shown to affect the nutritive value of barley for growing pigs, but there is a lack of information regarding the effect of this factor on pig performance. The barley variety “Riviera” was produced at nine different locations in Northern Ireland and formulated into diets (barley, soyabean meal and tallow at 650, 283 and 30 g/kg, respectively) for growing pigs. Diets were offered ad libitum to a total of 72 individually housed pigs from 8 to 11 weeks of age. Average start and end weights were 19 and 34 kg, respectively. Location of production had no significant effect on animal performance although a wide range was observed, which may be important under commercial conditions. Barley specific weight was not strongly correlated (r2 < 0.10) with any performance trait indicating that an alternative means of predicting the nutritive value of barely for pigs is required. A significant positive relationship was observed between barley β-glucan concentration and feed conversion ratio (r2 = 0.65).The authors acknowledge the Trustees of the Thomas Henry Scholarship, The Queen’s University of Belfast (QUB) and the Department of Agriculture and Rural Development for Northern Ireland (DARD), for the financial support which enabled this research to be undertaken

Appropriate parboiling steaming time at atmospheric pressure and variety to produce rice with weak digestive properties

Consumers with diabetes mellitus have shown interest in products with low postprandial glucose. To produce rice for this group of consumers, the effect of parboiling steaming time (0, 5, 15, 25, 35, and 45 min) and variety (NERICA1, NERICA7, WITA4, and IR841) on resistant, damaged starch fractions and glycemic response in rats was investigated. Resistant and damaged starch fractions were influenced by variety and steaming time but this was not the case for glycemic index. Nonparboiled NERICA7 and NERICA7 steamed for 25 min recorded the highest (10.07%) and lowest (2.49%) resistant starch fraction, respectively. Resistant starch correlated negatively with protein and sodium and positively with lipids. Damaged starch was high for WITA4 steamed for 45 min (26.80%) and low for nonparboiled NERICA1 (6.59%). Damaged starch correlated positively with lipid content and negatively with ash and total starch content. NERICA7 steamed for 35 min recorded the lowest postprandial glucose level 30 min after feeding (0.16 g/L), while WITA4 steamed for 15, 25, and 35 min and nonparboiled NERICA7 recorded higher levels (0.76, 0.91, 0.84, and 0.76 g/L, respectively). NERICA7 steamed for 35 min recorded both low glycemic and weak digestive properties because the glycemic index was lowest 120 min and increased steadily up to 180 min after feeding. We conclude that the digestive properties of rice depend both on the intrinsic properties of the variety and the parboiling steaming time

The interplay of α-amylase and amyloglucosidase activities on the digestion of starch in in vitro enzymic systems

In vitro hydrolysis assays are a key tool in understanding differences in rate and extent of digestion of starchy foods. They offer a greater degree of simplicity and flexibility than dynamic in vitro models orin vivo experiments for quantifiable, mechanistic exploration of starch digestion. In the present work the influence of α-amylase and amyloglucosidase activities on the digestion of maize and potato starchgranules was measured using both glucose and reducing sugar assays. Data were analysed through initialrates of digestion, and by 1st order kinetics, utilising logarithm of slope (LOS) plots. The rate and extent of starch digestion was dependent on the activities of both enzymes and the type of starch used. Potatorequired more enzyme than maize to achieve logarithmic reaction curves, and complete digestion. The results allow targeted design of starch digestion experiments through a thorough understanding of the contributions of α-amylase and amyloglucosidase to digestion rates