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

Flours from Spondias mombin and Spondias tuberosa seeds: Physicochemical characterization, technological properties, and antioxidant, antibacterial, and antidiabetic activities

Yellow mombin (Spondias mombin) and Brazil plum (Spondias tuberosa) seeds are byproducts of exploiting their pulp and currently have no relevant food or industrial applications. Thus, the present study aimed to evaluate the physicochemical, technological, and functional characteristics of flours obtained from yellow mombin (YMF) and Brazil plum (BPF) residues. The flours presented a high percentage of insoluble fiber (68.8-70.2 g/100 g) and low carbohydrate (2.7-4.0 g/100 g) and caloric (91.9-95.3 kcal) values. The flours showed potential for technological application. In addition, the highest concentration of total phenolic content (31.1-50.2 mg GAE/g) was obtained with 70% acetone, which provided excellent results for antioxidant capacity evaluated by 2,2'-azinobis (3-ethylbenzothiazoline-6-sulfonic acid) (81.0%-89.7%) and 2,2-diphenyl-1-picrylhydrazyl (60.6%-69.1%) radical scavenging capacity assays. Flour extracts in 70% acetone also exhibited inhibition of α-amylase (63.3%-78.8%) and amyloglucosidase (63.5%-71.0%). The antibacterial study revealed that extracts inhibited the growth of Escherichia coli, Burkholderia cepacia, and Burkholderia multivorans. Therefore, this study suggests the use of yellow mombin and Brazil plum residues for different food or industrial applications. PRACTICAL APPLICATION: The knowledge gained from this study will open a new approach to add value to yellow mombin and Brazil plum fruit seeds as sources of fiber and bioactive compounds, with promising application in the formulation of functional and nutraceutical products, benefiting both a sustainable environment and a sustainable industry.

Bringing back a forgotten legume-Sensory profiles of Australian native wattleseeds reveal potential for novel food applications

Documented as one of the oldest living civilizations, there is now evidence that Indigenous communities in Australia followed a sustainable lifestyle with well-designed agricultural practices and adequate physical activity. Commonly known as wattleseeds in Australia, unique cultivars of Acacia have been consumed by Indigenous Australians for over 60,000 years. This research used descriptive sensory profiling to develop a lexicon for the aroma and flavor profiles of four wattleseed species before and after being subjected to different processing techniques. The processing methods selected were pressure cooking, dry roasting, wet roasting, and malting. The species included were Acacia kempeana, Acacia adsurgens, Acacia colei, and Acacia victoriae. Sensory differences were observed between the different cultivars as well as between the different food processing techniques. Results show that wattleseed species diversity is a key driver in determining the aroma profile, while taste profiles are modified by the type of processing method applied. PRACTICAL APPLICATION: This study provides foundational knowledge on these culturally significant seeds, supporting practical opportunities to diversify the uses of wattleseeds in food products.

Mechanistic insights into the improving effects of germination on physicochemical properties and antioxidant activity of protein isolate derived from black and white sesame

Germination is a natural green technology to improve the nutritional and techno-functional quality of plant-based proteins. In this study, the mechanism of improving the functional and antioxidant properties of black and white sesame protein isolates (SPI) through germination process was investigated. Results showed that the surface hydrophobicity and sulfhydryl content increased significantly after germination, which were supported by multispectral analysis suggesting the exposed and unfolded conformational transition of germinated SPI. Moreover, the increased particle size was observed by microscopy analysis and reducing electrophoresis, which indicated that depolymerized protein molecules were rearranged to form protein aggregates during germination. The structural modification induced by germination contributed to the superior solubility (increased to 3.15-fold and 2.36-fold at pH 8 for black and white SPI, respectively), foaming capacity (increased to 3.99-fold and 1.69-fold, respectively), emulsifying ability (increased to 2.84-fold and 2.71-fold, respectively), and diverse chemical antioxidant activities (increased up to 5.60-fold) of SPI in both varieties. This was the first comprehensive study to investigate germination as a promising technology for obtaining high-quality SPI.

Antioxidant activities, phenolic compounds, and mineral composition of seed from Acacia retinodes, A. Provincialis and A. Tenuissima

Seeds of the species Acacia retinodes, A. provincialis, and A. tenuissima) from different growing locations were analysed for their mineral composition, free and bound polyphenols, and flavonoids. Previous research has studied these compounds in only a limited number of Acacia species, and only one study reports significant differences between three species. All species were rich in potassium (353 - 427 mg/100 g), sodium (14 - 240 mg/100 g) and iron (7 - 8 mg/100 g). The free polyphenol extracts of all species had higher total phenolic content, total flavonoid content and antioxidant activities than their bound counterparts, indicating the possibility of higher bioavailability than the bound polyphenol extracts. The predominant phenolic compounds found in the Acacia polyphenol seed extracts were 6-Hydroxy-2-methylindole and 2,2'-Methylenebis(6-tert-butyl-methylphenol), though no phenolic compounds were identified in the bound extracts of A. retinodes Grampians and A. provincialis Tarrington. Other compounds identified in the seed extracts include sucrose, d-fructofuranose and d-pinitol.

Effects of incorporating processed Acacia seed as an emulsifying agent on the quality attributes of beef sausage

In this study, partial or full replacement of 6% soy protein isolate (SPI) with 2, 4 and 6% roasted Acacia seed flour (ASRo) and Acacia seed protein concentrates (ASPC) in emulsified beef sausage were investigated. Emulsion stability and cooking loss were lower in samples formulated with ASPC at all levels and control samples compared to ASRo formulated samples. ASRo generated softer and less chewy sausages than ASPC. Cooked 2% ASPC sausages had similar L* and a* values as the control but with lower colour difference (ΔE) values that were similar to cooked 6% SPI sausages' values. An organized protein network structure was observed in the sausages formulated with ASPC at all levels and in the control samples. Therefore, ASPC, particularly at 2 and 4% inclusion, can be used as a functional ingredient to prepare emulsified beef sausages with good quality attributes.

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.

Australian native fruits and vegetables: Chemical composition, nutritional profile, bioactivity and potential valorization by industries

Australian native plants have adapted themselves to harsh climatic conditions enabling them to produce unique and high levels of secondary metabolites. Native fruits and vegetables have been an integral part of the Indigenous Australian diet and Bush medicine for centuries. They have recently gained popularity owing to their rich dietary fiber, minerals, polyphenolic and antioxidant contents. This review presents a comprehensive summary and critical assessment of the studies performed in the last few decades to understand the phytochemical and nutritional profiles and therapeutic properties of Australian native fruits and vegetables. Furthermore, the potential of these fruits and vegetables as functional food ingredients and in the prevention and treatment of different diseases is discussed. Research on the nutritional and phytochemical profiles and therapeutic activity of Australian vegetables is limited with most studies focused on native fruits. These fruits have demonstrated promising antioxidant, anticancer, anti-inflammatory and antimicrobial activities mostly in in vitro models. More research to a) identify novel bioactive compounds, b) define optimal post-harvest and extraction methods, and c) understand molecular mechanisms of pharmacological activity through preclinical and clinical studies is prudent for the prospective and wider use of Australian native fruits and vegetables by the food, pharmaceutical, and nutraceutical industries.

The Framework for Responsible Research With Australian Native Plant Foods: A Food Chemist's Perspective

Australia is a rich source of biodiverse native plants that are mostly unstudied by western food science despite many of them being ethnofoods of Australian Indigenous people. Finding and understanding the relevant policy and legal requirements to scientifically assess these plants in a responsible way is a major challenge for food scientists. This work aims to give an overview of what the legal and policy framework is in relation to food chemistry on Australian native plant foods, to clarify the relationships between the guidelines, laws, policies and ethics and to discuss some of the challenges they present in food chemistry. This work provides the framework of Indigenous rights, international treaties, federal and state laws and ethical guidelines including key legislation and guidelines. It discusses the specific areas that are applicable to food chemistry: the collection of plant foods, the analysis of the samples and working with Indigenous communities. This brief perspective presents a framework that can be utilized by food chemists when developing responsible research involving plant foods native to northern Australia and can help them understand some of the complexity of working in this research area.