Effects of Roasting on the Characteristics of Australian Wattle (Acacia victoriaeBentham) Seed and Extracts

Compositional and functional changes in Acacia tenuissima seeds due to processing

The chemical, functional, anti-nutritional, and antioxidant composition of raw and roasted Acacia tenuissima seeds were determined to evaluate the impact of heat processing. The raw seeds were relatively high in protein (25.2 %), fat (10.3 %) and crude fiber (13.2 %), potassium (760 mg/100 g), magnesium (111 mg/100 g) and calcium (66.5 mg/100 g). Linolenic (34 %), margaric acid (24 %) and oleic acid (16 %) were the notable fatty acids present in the raw seeds. The proximate and fatty acid composition of A. tenuissima were not significantly impacted by roasting. Acacia tenuissima flour had excellent foaming capacity, foaming stability and water solubility making it a potential functional ingredient in the baking industry. Anti-nutrients were present in the raw seeds but at low quantities (trypsin inhibitor activity: 0.22 TIU/g, saponin: 2.29 %) while the antioxidant activity was high at 94 % compared to other Acacia species. Only the water solubility and trypsin inhibitor activity of A. tenuissima decreased significantly after roasting. Roasting had no significant impact on the seed constituents and their properties except for water solubility, and trypsin inhibitor activity which decreased, making it an ideal ingredient to be used in baked products.

Nutritional and techno-functional properties of Australian Acacia seed flour: Effects of roasting on chemical composition, physicochemical properties, and in vitro digestibility and intestinal iron absorption

Acacia seed (AS) is rich in protein and iron but contains protease inhibitors that can reduce protein digestibility (PD). The seeds are generally roasted prior to consumption, although no information on the PD of roasted AS is available. This study investigated the effect of roasting time (5, 7 and 9 min at 180 °C) on the chemical composition, physicochemical properties, and in vitro PD and intestinal iron absorption of three wild harvested Australian AS species, Acacia victoriae, A. coriacea and A. cowleana. Roasting A. victoriae and A. coriacea seeds for 7 min significantly increased PD in the seeds by 36 and 61 %, respectively. A 9-min roasting time was required to achieve 75 % reduction in trypsin inhibitor activity in A. coriacea seed, while a shorter roasting time (RT) was sufficient to achieve similar reduction rates in the other two Acacia species. Among the functional properties, water and oil absorption capacities were significantly enhanced as RT increased. The starch granules in 7- and 9-min roasted A. victoriae seed flour detached from the protein matrix while random coil increased in 7-min roasted A. victoriae and 9-min roasted A. coriacea and A. cowleana, thus, contributing to enhanced PD. Although the SDS-PAGE in 7- and 9-min roasted A. cowleana samples showed reductions in the intensity of bands for high molecular weight proteins, PD was not affected by RT. However, intestinal iron absorption was not significantly affected by roasting as compared to raw digesta samples. Compared to commercial roasted Acacia seed, the considerably shorter RT used in this study improved PD in the AS flour with less adverse effects on techno-functional properties.

Food resilience in a dark catastrophe: A new way of looking at tropical wild edible plants

A global sun-blocking catastrophe is more plausible than anyone would like to think. Models have consistently shown the devastating effects these events could have to the world's agricultural systems for upwards of 15 years. New shade-, drought-, and cool-tolerant crops and more food stockpile sources must be found if there would be any hope of feeding the global population in such a scenario. Wild edible plants (WEPs) are important buffers of food security to indigenous peoples, impoverished peoples, and those in areas with erratic growing seasons across the globe. Here, we suggest WEP species that have the potential to be scaled up through cultivation in post-catastrophe conditions, and the use of foraged food stockpiles to function as stop-gap foods until conventional agriculture returns. We also propose policy initiatives for habitat protection, education programs, and general preparedness.

Effect of germination, roasting, and variety on physicochemical, techno-functional, and antioxidant properties of chickpea (Cicer arietinum L.) protein isolate powder

Chickpeas are a very important part of the human diet due to their nutritional and bioactive composition. Ethiopia is one of the top chickpea producers and consumers of chickpea-based products daily. However, limited studies were conducted on the effect of common processing methods, roasting and germination, on techno-functional and nutritional properties of chickpea protein isolates. Two varieties of chickpea, Arerti (Kabuli type) and Natoli (Desi type), were selected and treated with different roasting temperature (150 and 180 °C) and germination time (24, 48, and 72 h). The protein was isolated with alkaline-solubilization followed by isoelectric precipitation. Freeze-dried isolates were investigated for proximate composition, techno-functional properties, antioxidant properties, and antinutritional content. Chickpea protein isolates (CPIs) mean protein content was between 79.72 and 87.43%, comparatively lower for those from roasted and higher for those from germinated chickpea. Mean values of CPIs’ water holding capacity (WHC), oil holding capacity (OHC), protein solubility (PS), foaming capacity (FC), and Emulsifying capacity (EC) for both varieties were in a range of 1.07–2.47 g/g, 1.40–2.21 g/g, 43.88–69.99%, 14.00–94.00%, and 56.44–84.16%, respectively. Roasting at 150 °C improved most of the techno-functional properties (WHC, OHC, PS, and FC) while roasting at 180 °C negatively affected almost all the techno-functional properties. Both heat treatments significantly increased the antioxidant properties of the isolates. Germination for 72 h was the best treatment in improving all antioxidant properties. CPIs from treated chickpea had lower antinutritional content than those from native chickpea except for phytate on Natoli variety where no statistical difference (p > 0.05) was observed. The finding showed that based on the intended use the different techno-functional properties of the isolates can be altered by applying those treatments. Proximate, techno-functional, antioxidant, and antinutritional characters indicated that CPIs can be a good ingredient for the food industry to formulate functional foods.

Nutritional, anti-nutritional, antioxidant, physicochemical and functional characterization of Australian acacia seed: effect of species and regions

BACKGROUND

Acacia seed (AS) is an underutilized legume widely distributed in the world, with majority of the species (>70%) found in Australia. Generally, the seeds are not only rich in protein, dietary fibre and potassium, but also possess anti-nutritional compounds. In recent years, there have been an increase in the cultivation of some Australian acacia species such as Acacia victoriae, Acacia cowleana and Acacia coriacea from different regions. However, there is limited information on the composition, anti-nutrients, antioxidant and functional properties of flour from these widely grown Australian AS species. Thus, the present study aimed to assess the properties of these Australian AS species from different geographical regions.

RESULTS

The A. cowleana and A. coriacea were characterized by high protein, fat, potassium and soluble carbohydrate. However, higher starch and fibre contents were present in A. victoriae. Greater amounts of anti-nutrients, total phenolics and flavonoids were found in A. cowleana and A. coriacea seeds, whereas A. victoriae had higher 2,2-diphenyl-1-picrylhydrazyl radical-scavenging capacity. A. victoriae and A. coriacea demonstrated the highest water absorption and solubility index, respectively. However, A. cowleana showed the highest oil absorption index. There was less variation in the composition and properties within species from different regions.

CONCLUSION

All samples showed promising nutritional characteristics, although with sufficient diversity to indicate that Australian acacia seeds can be utilized to develop a range of new (functional) food products. Overall, the information obtained will help the food industries with the selection of AS species for food application.

Mid-Infrared Spectroscopy as a Rapid Tool to Qualitatively Predict the Effects of Species, Regions and Roasting on the Nutritional Composition of Australian Acacia Seed Species

In recent times, the popularity of adding value to under-utilized legumes have increased to enhance their use for human consumption. Acacia seed (AS) is an underutilized legume with over 40 edible species found in Australia. The study aimed to qualitatively characterize the chemical composition of 14 common edible AS species from 27 regions in Australia using mid-infrared (MIR) spectroscopy as a rapid tool. Raw and roasted (180 °C, 5, 7, and 9 min) AS flour were analysed using MIR spectroscopy. The wavenumbers (1045 cm⁻¹, 1641 cm⁻¹, and 2852–2926 cm⁻¹) in the MIR spectra show the main components in the AS samples. Principal component analysis (PCA) of the MIR data displayed the clustering of samples according to species and roasting treatment. However, regional differences within the same AS species have less of an effect on the components, as shown in the PCA plot. Statistical analysis of absorbance at specific wavenumbers showed that roasting significantly (p < 0.05) reduced the compositions of some of the AS species. The results provided a foundation for hypothesizing the compositional similarity and/or differences among AS species before and after roasting.

Overall Nutritional and Sensory Profile of Different Species of Australian Wattle Seeds (Acacia spp.): Potential Food Sources in the Arid Semi-Arid Regions

Wattle seed (Acacia spp.) is a well-known staple food within indigenous communities in Australia. A detailed investigation of the overall nutritional and sensory profile of four abundant and underutilized Acacia species-A. coriacea, A. cowleana, A. retinodes and A. sophorae-were performed. Additionally, molecular weight of protein extracts from the wattle seeds (WS) was determined. The seeds are rich in protein (23-27%) and dietary fibre (33-41%). Relatively high fat content was found in A. cowleana (19.3%), A. sophorae (14.8%) and A. retinodes (16.4%) with oleic acid being the predominant fatty acid. The seeds contained high amounts of essential amino acids (histidine, lysine, valine, isoleucine and leucine). A. coriacea is rich in iron (43 mg/kg), potassium (10 g/kg) and magnesium (1.7 g/kg). Pentose (xylose/arabinose), glucose, galactose and galacturonic acids were the major sugars found in the four species. Raw seeds from A. sophorae, A. retinodes and A. coriacea have the highest protein molecular weight, between 50-90 kDa, 80 kDa and 50-55 kDa, respectively. There was variation in the sensory profile of the WS species. This study showed that the four WS species have good nutritional value and could be included in human diet or used in food formulations.

In vitro gastrointestinal digestion of glabrous canaryseed proteins as affected by variety and thermal treatment

Glabrous or hairless canaryseed is a nutritional grain that could be a good addition to the diet if approved as a novel food. To assess the impact of thermal treatment on its digestibility; raw, roasted or boiled flours prepared from three different varieties of glabrous canaryseed were subjected to in vitro gastrointestinal digestion conditions and the effect on protein electrophoretic profiles was examined using sodium dodecyl sulphate polyacrylamide gel electrophoresis (SDS-PAGE). Roasting was done by dry-heat in an oven at 176 °C for 12 min whereas boiling was done in water at 98 °C for 12 min. SDS-PAGE showed approximately twenty-five protein bands in the undigested raw flour with molecular masses (MM) ranging from <14 kDa to >97 kDa. The dominant proteins had low MM, between the ranges of ~57 to 12 kDa. Roasting markedly altered the protein electrophoretic profile with the appearance of large molecular weight aggregates. Canaryseed proteins were more easily digested after thermal treatment and under sequential gastric-duodenal conditions than under gastric or duodenal conditions alone. Furthermore, roasting appeared to have a greater impact on in vitro protein digestibility than boiling.