Background and Objectives: There is confusion as to which component of the Opuntia spp. cacti has demonstrated anti-hyperglycemic effects or anti-diabetic properties. It is important to clarify these health benefits due to the increasing need for prevention and treatment of chronic diseases. The aim of this review is to identify the effects of Opuntia spp. cacti consumption on biomedical measures; glucose and insulin with consideration of its’ components; fruit, leaf and combined or unidentified Opuntia spp. products. Materials and Methods: Prior to commencing the searches, this systematic review was registered with PROSPERO (CRD42018108765). Following the PRISMA 2009 guidelines, six electronic databases (Food Science and Technology Abstracts (EBSCO), Medline, Scopus, CINAHL, Web of Science and Cochrane) were searched for articles investigating the effect of Opuntia spp. consumption on glucose and insulin in humans. Results: Initially, 335 articles were sourced and filtered by exclusion criteria (human interventions, control trials and articles published in English) resulting in 20 relevant articles. The included studies were characterized by such plant components as fruit (n = 4), cladode (n = 12), and other Opuntia spp. products (n = 4), further separated by clinical populations (‘healthy’, hyperlipidemic, hypercholesterolemic, Type 2 Diabetes Mellitus). The findings of this review indicate variations in effects between cacti components and products. Cladode and select Opuntia spp. products predominately demonstrated significant reductions in serum glucose and insulin, indicating potential as a functional food candidate. Prickly Pear fruit was predominately reported to have no significant effects on glucose or insulin. The quality of evidence appeared to vary based on the type of Opuntia spp. product used. Studies that used specifically the fruit or cladode had high risk of bias, whereas studies which used combined Opuntia spp. products had a lower risk of bias. Numerous mechanisms of action were proposed where positive findings were reported, with emphasis on dualistic glucose-dependent and independent actions, however, mechanisms require further elucidation. Conclusion: Currently, there is a lack of evidence to support the recommendation of using Opuntia spp. fruit products as an alternative or complementary therapy in the reduction of risk or management of Type 2 Diabetes Mellitus. The Cladode does however show promise in potential glucose-lowering effects which warrant further investigation.

Honey is a supersaturated sugar solution produced from plant nectar, with its composition influenced by geographic and floral origins, and with several properties contributing to its health-related abilities. This study aimed to determine the bioactive composition, antioxidant characteristics, antibacterial activity, and physicochemical properties of commercial Australian honeys. In total, 42 commercial Australian honeys were selected, and categorised according to front-label descriptions. Honeys were analysed: quality (Hydroxymethylfurfural); colour (colour intensity, L*,a*,b*); bioactive composition (phenolic, flavonoid, and carotenoid content); antioxidant characteristics (DPPH, CUPRAC, FRAP); antibacterial activity (MIC₅₀); physicochemical properties (pH, TSS, viscosity, a_w). Colour intensity correlated with each assessed bioactive compound and antioxidant characteristic (p ≤ 0.001). MIC₅₀ (S. aureus) was associated with FRAP and a_w, suggesting mechanisms of action for honey's antibacterial activity. Manuka-type honeys had higher colour intensity (1440 (98.5) mAU) than other categories (p ≤ 0.05), and consistently higher bioactive and antioxidant properties. This provides the potential to inform antioxidant-related health outcomes.

The current dietary recommendations for cardiovascular disease (CVD) risk reduction include increased fruit and vegetable consumption. The Opuntia spp., Prickly Pear (PP) fruit is rich in dietary fiber and may have lipid-lowering effects but it is often confused with the PP stem/leaf (Cladode (CLD)), or not identified. The efficacy of the PP fruit and CLD in reducing CVD risk is a growing area of research. This systematic review (PROSPERO: CRD42018110643), examined the effects of consuming the Opuntia spp. components (PP or CLD) on CVD risk factors, specifically total cholesterol (TC), low-density lipoprotein cholesterol (LDL-C), high-density lipoprotein cholesterol (HDL-C) and triglycerides (TG). The review, performed from February through September 2019, used resources available through Food Science and Technology Abstracts (EBSCO), Medline, Scopus, CINAHL, Web of Science and Cochrane databases. Eleven articles met the inclusion criteria, which characterised Opuntia spp. products as either PP (n = 6), CLD (n = 4) or commercial products' (n=1). Effects were investigated in healthy and obese populations as well as those with metabolic illnesses, specifically type 2 diabetes and metabolic syndrome. PP consumption was associated with significant reductions in TC (p < 0.05) in all but one included study, whereas in the remaining studies (n=6), LDL-C levels decreased (p < 0.05). Separately, the effect of CLD consumption on lipids was small with one study reporting a significant increase in plasma HDL-C in a subgroup of participants (>45 years of age) following consumption of a patented CLD powder product. It is plausible, that differences in overall effect may be due to compositional distinctions between CLD and PP, such as fiber composition. Care must be taken in future studies to accurately report the identity of the selected components of Opuntia spp.

Prickly Pear (Opuntia ficus indica) is commonly consumed but limited by short harvesting seasons and shelf life. Drying may resolve such issues. The effects of different methods were examined to investigate the phytochemicals in Australian prickly pear (PP). White, orange and purple fruits were dried using freeze‐drying, microwave, draft‐oven, and dehydrator‐drying (35°C, 55°C, and 75°C). Total Phenolic Content (TPC), Total Flavonol Content (TFC), Total Betalain Content (TBC), Betacyanin (BE), and Betaxanthin (IE) and antioxidant characteristics (2,2‐diphenyl‐1‐picrylhydrazyl [DPPH], Cupric Ion Antioxidant Reducing Capacity [CUPRAC], and Ferric Reducing Antioxidant Power [FRAP]) were determined as methanolic extracts (skin/flesh). The highest content is as follows: TPC (149 ± 5.06 µg _GAE ; microwave; purple skin), TFC (76.6 ± 1.98 µg _CE ; microwave; purple‐skin), TBC (4.17 ± 0.846 mg/100 g; freeze‐dried; orange‐skin and flesh), BE (2.29 ± 1.00 mg _BE /100 g; freeze‐dried; purple‐flesh), IE (3.42 ± 0.569 mg _IE /100 g; freeze‐dried; purple‐flesh); DPPH (224 ± 41.2 µM _TE ; freeze‐dried; white‐flesh), CUPRAC (2,937 ± 43.3 µM _TE ; microwave; purple‐skin) and FRAP (1,377 ± 27.0 µM _TE ; microwave; purple‐skin). Significant differences ( p < 0.05) occurred between drying methods. When compared to freeze drying, microwaving, in some cases elicited the highest content. Practical applications: The gap between the nutrient‐dense prickly pear fruit, and its consumption is prominent, particularly in Australia. This is potentially the consequences of social misconceptions, a short harvesting season and shelf life, thus potentially contributing to Australia's growing food waste challenge. Therefore, such obstacles could be reduced with the use of the most appropriate drying technique in order to extend the products shelf life. Our manuscript investigates the effect of different drying techniques on the phytochemical content of the prickly pear fruit. The investigated drying methods were considered accessible to small agricultural producers, the predominant farmers for this fruit in Australia. The findings of this paper can be potentially implemented in agricultural practice, assisting with year‐round food supply and reduce on‐site foods waste.

Prickly Pear (PP) is often overlooked due to its’ short shelf-life. Juicing may improve marketability but often affects quality, thereby warranting investigation. Purple PP (whole (WF) and flesh (FF)) was juiced using blenders; stick (SB) and jug (JB); and juicers; commercial (CJ) and cold-pressed (CP). Juices and methanolic (70%) pomace extracts were analysed for; bioactives; Total Phenolic (TPC; µg_GAE/mL), Flavonoid (TFC; µg_CE/mL) and Betalain Content (TBC; mg/100 g; Betacyanin; BE; Betaxanthin; IE); and antioxidant characteristics; DPPH, FRAP (µM_TE) and vitamin C (mg_AAE/mL). Juicing techniques had effects on phytochemicals in; juice: TPC (WF/FF; p = 0.022–0.025), TFC (FF; p = 0.034), Betacyanin (WF/FF; p = 0.029–0.026), FRAP (WF/FF; p = 0.016–0.024) and Vitamin C (WF/FF; p = 0.015–0.016); and pomace: TPC (WF/FF; p = 0.015), TBC (FF; p = 0.034), Betacyanin (FF; p = 0.047), Betaxanthin (FF; p = 0.017), DPPH (WF/FF; p = 0.016–0.024), FRAP (WF/FF; p = 0.015–0.023) and Vitamin C (WF/FF; p = 0.016–0.022). Processing-style (blend/juice) affected; TPC, DPPH and FRAP in juice and pomace. Overall, fruit-preparation (WF/FF) had minimal effects. Additionally, correlations existed between; juice TFC and TBC (p = 0.001; τ = −0.044); TBC and vitamin C (p = 0.001; τ = −0.637); pomace TPC and DPPH (p = 0.003; τ = 0.440), TPC and vitamin C (p = 0.011; τ = 0.440); and TFC and FRAP (p = 0.001; τ = 0.519). The best methods overall for juice were SB (FRAP), JB (TPC, TBC), CJ (TFC) and CP (DPPH, VitC); and for pomace extracts; SB(FRAP), JB (TPC, VitC), CJ(TFC), and CP (TBC, DPPH).