Raffinose/Sucrose/D-Glucose Assay Kit

Procedures for the measurement of starch, starch damage (gelatinised starch), resistant starch and the amylose/amylopectin content of starch, β-glucan, fructan, glucomannan and galactosyl-sucrose oligosaccharides (raffinose, stachyose and verbascose) in plant material, animal feeds and foods are described. Most of these methods have been successfully subjected to interlaboratory evaluation. All methods are based on the use of enzymes either purified by conventional chromatography or produced using molecular biology techniques. Such methods allow specific, accurate and reliable quantification of a particular component. Problems in calculating the actual weight of galactosyl-sucrose oligosaccharides in test samples are discussed in detail.

An American Association of Cereal Chemists/AOAC collaborative study was conducted to evaluate the accuracy and reliability of an enzyme assay kit procedure for measurement of total starch in a range of cereal grains and products. The flour sample is incubated at 95 degrees C with thermostable alpha-amylase to catalyze the hydrolysis of starch to maltodextrins, the pH of the slurry is adjusted, and the slurry is treated with a highly purified amyloglucosidase to quantitatively hydrolyze the dextrins to glucose. Glucose is measured with glucose oxidase-peroxidase reagent. Thirty-two collaborators were sent 16 homogeneous test samples as 8 blind duplicates. These samples included chicken feed pellets, white bread, green peas, high-amylose maize starch, white wheat flour, wheat starch, oat bran, and spaghetti. All samples were analyzed by the standard procedure as detailed above; 4 samples (high-amylose maize starch and wheat starch) were also analyzed by a method that requires the samples to be cooked first in dimethyl sulfoxide (DMSO). Relative standard deviations for repeatability (RSD(r)) ranged from 2.1 to 3.9%, and relative standard deviations for reproducibility (RSD(R)) ranged from 2.9 to 5.7%. The RSD(R) value for high amylose maize starch analyzed by the standard (non-DMSO) procedure was 5.7%; the value was reduced to 2.9% when the DMSO procedure was used, and the determined starch values increased from 86.9 to 97.2%.

Our study investigated the effectiveness of 446 strains of lactic acid bacteria (LAB) belonging to different species and isolated from diverse sources (food, human, and animal) as potential probiotic candidates, with the perspective of producing dietary supplements or pharmacological formulations suitable for enhancing gastrointestinal digestion. The survival capability of all the isolates under harsh gastrointestinal tract conditions was evaluated, in which only 44 strains, named high-resistant, were selected for further food digestibility investigations. All 44 strains hydrolyzed raffinose and exhibited amino and iminopeptidase activities but at various extents, confirming species- and strain-specificity. After partial in vitro digestion mimicking oral and gastric digestive phases, food matrices were incubated with single strains for 24 h. Fermented partially digested matrices provided additional functional properties for some investigated strains by releasing peptides and increasing the release of highly bio-accessible free phenolic compounds. A scoring procedure was proposed as an effective tool to reduce data complexity and quantitively characterize the probiotic potential of each LAB strain, which could be more useful in the selection procedure of powerful probiotics.

The composition and properties of potatoes have been comprehensively studied; however, effects of different cultivation periods on these factors remain unclear. Hence, we aim to provide insights for cultivating potatoes with desirable properties by controlling the potato growth time and cultivars. Physico-chemical quality characteristics of three potato cultivars-Chubaek, Superior, and Atlantic-were analysed at different cultivation periods (80, 90, and 100 days). Regardless of cultivation period, total starch and amylose content of the cultivars was as follows: Atlantic > Superior > Chubaek, whereas sucrose and glucose content was in reverse order. The Atlantic cultivar showed the highest dry matter content, whereas Chubaek showed the highest moisture content. In all cultivars, glutamic acid and aspartic acid were the predominant amino acids. Peak viscosity was the highest in Atlantic cultivar and increased as the cultivation period progressed. Final, peak, and breakdown viscosities were positively correlated with starch and amylose content and negatively correlated with glucose, sucrose, and most amino acid content. Hierarchical clustering heatmaps showed that all three cultivars cultivated for 100 days exhibited different patterns from those cultivated for 80 and 90 days. Overall, quality characteristics of the potatoes were more influenced by genetic characteristics than by the cultivation period.

Raffinose family oligosaccharides (RFOs) are known to have important physiological functions in plants. However, the presence of RFOs in legumes causes flatulence, hence are considered antinutrients. To reduce the RFOs content to a desirable limit without compromising normal plant development and functioning, the identification of important regulatory genes associated with the biosynthetic pathway is a prerequisite. In the present study, through comparative RNA sequencing in contrasting genotypes for seed RFOs content at different seed maturity stages, differentially expressed genes (DEGs) associated with the pathway were identified. The DEGs exhibited spatio-temporal expression patterns with high RFOs variety showing early induction of RFOs biosynthetic genes and low RFOs variety showing a late expression at seed maturity. Selective and seed-specific differential expression of raffinose synthase genes (AhRS14 and AhRS6) suggested their regulatory role in RFOs accumulation in peanut seeds, thereby serving as promising targets in low RFOs peanut breeding programs. Despite stachyose being the major seed RFOs fraction, differential expression of raffinose synthase genes indicated the complex metabolic regulation of this pathway. The transcriptomic resource and the genes identified in this study could be studied further to develop low RFOs varieties, thus improving the overall nutritional quality of peanuts.

Compositional analyses of sequentially pearled fractions of high-tannin (HT, Athena) and low-tannin (LT, Snowbird) faba bean (Vicia faba L.) cultivars demonstrated that the decreasing trend of protein, ash and total dietary fibre (TDF) contents from outer to inner layers was offset by starch contents. LT and HT proteins were positively correlated (r = 0.9, P < 0.0001) with ash and total dietary fibre contents while negatively correlated (r = −0.9, P < 0.0001) with starch contents with increasing degree of pearling. The 55-57 % single-step pearling flour had a higher (P < 0.05) protein content (LT:39.07 ± 0.06 % and HT:37.37 ± 0.03 %, N × 6.25) as compared to whole beans (LT:30.51 ± 0.39 and HT:29.63 ± 0.20 %). The starch contents of the pearled beans were significantly higher (P < 0.05) than whole beans. These single-step pearling flour fractions subjected to aqueous fractionation to isolate proteins (>94 % purity) resulted in starch isolates and dietary fibre concentrates as co-products. Hybrid fractionation had minimal impact on the native protein secondary structures where β-sheets were dominant. This study suggests that the inclusion of pearling as an upstream processing step prior to wet fractionation of both LT and HT faba beans has the potential to generate novel “clean label” ingredients for the food industry.

Snack alternatives based on common beans (Phaseolus vulgaris L.) have been developed to promote pulse consumption. The purpose of this study was to evaluate the chemical composition, sensory acceptance and the effect of common bean baked snack (CBBS) consumption on blood lipid levels in participants with overweight and altered blood lipid levels. A sensory evaluation by 80 untrained judges was carried out using a hedonic scale. A randomized crossover 2 × 2 trial was performed, where 20 participants with overweight and one blood lipid alteration consumed 32 g of CBBS or did not consume it (control) for four weeks. Blood samples were taken to quantify the triglycerides, total cholesterol, LDL-c, HDL-c, ApoB-100, glucose and insulin. Furthermore, anthropometric, dietary and physical activity parameters were recorded. The overall acceptance of CBBS was similar compared to popcorn (p > 0.05). The consumption of CBBS reduced the apolipoprotein B-100 levels (p = 0.008). This reduction could be associated with the additional dietary fiber consumption during the CBBS period (p = 0.04). Although it did not improve any other blood lipid or glucose parameters (p > 0.05), it did not affect them either, which means that the CBBS could be consumed without compromising cardiovascular health.

Currently, the predominant process for soy protein concentrate (SPC) production is aqueous ethanol washing of hexane-extracted soy meal. However, the use of hexane is less desired, which explains the increased interest in cold pressing for oil removal. In this study, cold-pressed soy meal was used as the starting material, and a range of water/ethanol ratios was applied for the washing process to produce SPCs. Washing enriched the protein content for the SPCs, regardless of the solvent used. However, we conclude that washing with water (0% ethanol) or solvents with a high water/ethanol ratio (60% and above) can be more advantageous. Washing with a high water/ethanol ratio resulted in the highest yield, and SPCs with the highest protein solubility and water holding capacity. The water-only washed SPC showed the highest viscosity, and formed gels with the highest gel strength and hardness among all the SPCs at a similar protein concentration. The variations in the functionality among the SPCs were attributed to protein changes, although the effects of non-protein constituents such as sugar and oil might also be important. Overall, the aqueous ethanol washing process combined with cold-pressed soy meal created SPCs comparable to commercial SPC in terms of composition, but with varied functionalities that are relevant for novel soy-food developments.

The aim of the study was to determine the effect of seed production environment in Sri Lanka on seed development, maturation, and subsequent seed quality. The experiment was conducted at six production environments, three locations (Mahailluppalama (M1), Polonnaruwa (POL), and Aluttarama (ALU), over two planting cycles (P1, P2). Seed development and maturation, seed and seedling quality characteristics were evaluated at five reproductive (R6, R7, R8, R8 + 5 and R8 + 10) maturity stages. The study infers that production environment at the late reproductive (LR) stage (R6-R8) was critical in determining the seed quality. If the LR stage coincided with cumulative rainfall (RF) over 100 mm or above 75% relative humidity (RH), categorized as wet environment, around 27.5 days was required for the completion of seed maturation compared with only 17.5 days in dry environment. Seed lots from dry environment during LR stage surpassed the minimum quality standards (75% final germination, germination index of 300, germination rate index of 25% per day, seedling vigor index of 2500 and 15 µmol/min/mg FW catalase activity) at maturity stage R7 onwards, while this only occurred at maturity stage R8 for wet environment. A significant negative correlation (r = -0.50 **) was observed between glucose content, antioxidant enzyme activities and germination percentage. In conclusion, the findings provide useful information for the expansion of areas for seed production in Sri Lanka.

Starch-sugar homeostasis and starch molecular configuration regulates the dynamics of starch digestibility which result in sweet sensory perception and eliciting glycemic response, which has been measured in vitro as inherent glycemic potential (IGP). The objective of the research was to understand the key determinants of IGP as well as sweetness in different Pearl millet (PM) genotypes. To understand the intricate balance between starch and sugar, total starch content (TSC) and total soluble sugars (TSS) were evaluated. Higher concentrations of TSC (67.8%), TSS (2.75%), glucose (0.78%) and sucrose (1.68%) were found in Jafarabadi Bajra. Considering the role of compact molecular configuration of starch towards digestibility, X-ray powder diffraction (XRD) analysis was performed. A-type crystallinity with crystallinity degree (CD %) ranged from 53.53–62.63% among different genotypes, where the least CD% (53.53%) was found in Jafarabadi Bajra. In vitro starch hydrolyzation kinetics carried out to determine IGP, revealed a maximum of 77.05% IGP with minimum 1.42% resistant starch (RS) in Jafarabadi Bajra. Overall our results suggest higher sweet sensory perception of Jafarabadi Bajra which is contributed by the matrix composition with least molecular compactness of starch. Also, the interdependence among starch quality parameters; CD%, IGP, RS and amylose has also been discussed.