## 3 Results
### Mineral Contents
#### 3.3.2 Essential Micro-Minerals  
Iron is an essential micro-mineral for bodily functions, including acting as an oxygen carrier in the blood, and being a component of some enzymes in tissues [57]. In the present study, iron content in SGP was found to be 23 mg/kg DW, indicating that consumption of 0.4 to 0.5 kg/day of SGP would meet the recommended dietary allowance (RDA) of iron of 9-15 mg per day (children), 8-18 mg per day (women), and 8 mg per day (men) [58], as a part of a balanced diet. The most vulnerable population affected by iron deficiency are infants, children, and women of childbearing age [33]. According to FAO/WHO [56], the labelling of food as being 'high in' or a'source of' depends on the nutrient reference value (NRV). If the NRV of a food for iron is 10-19%, then the food is considered to be a good source of iron; however, if the food has a daily value of more than 20%, then it is considered to be high in iron content. Hence, potentially SGP could be considered to be a 'high in' source of iron for a diet.  
The levels of manganese in SGP (8.8 mg/kg DW) were within the range reported by [PERSON], et al. [4] (6-110 mg/kg DW), and similar to _R. bilineatus_ (8.2 mg/kg DW) [8]. The variations in the content of nutrients in these studies depend on several factors, such as species/variety studied, feed, location of harvesting, the reproductive cycle of the insects, and any pre-processing steps used during the post-harvest handling of the insects [1]. The nutrient quality of various foods can be altered by different food processing methods such as boiling or frying [59]. So far, the effect of the various food preparation methods on the mineral content of various insect materials has not been fully investigated [60].  
Selenium was detected in SGP (0.03 mg/kg). Selenium is a trace element, and its deficiency is reported to be associated with various health implications such as suppressed biosynthesis of key selenoproteins, low lipid accumulation, high glutamine catabolism, and hypoglycaemia [61]. However, levels of selenium higher than the recommended intake of 0.45 mg/day can increase lipogenesis, cholesterol biosynthesis, and protein biosynthesis [61]. Chromium is another essential micronutrient for humans and plays an important role in regulating blood sugar levels. Consumption of 100-200 g of SGP that contains 0.25 mg/kg DW of chromium can provide the recommended daily intake for an adult (0.02-0.04 mg) [58].  
The nutrient reference value (NRV) for zinc is reported to be 15-30 mg/day [56], and hence \(\sim\)300 g of SGP would fulfil the daily requirement of zinc. Compared to superworm (77 mg/kg DW) [60], the zinc content was found to be relatively high in SGP (83 mg/kg DW) (Table 2), and this was similar to that found by [PERSON], et al. [4] (80-90 mg/kg DW). Zinc is an essential mineral for more than 300 enzymes involved in the metabolism of nutrients and facilities cell and organ integrity and the immune system [29]. In the present study, SGP contained 8.3 mg/kg DW copper, which is lower than those reported for _R. ferrugineus_ (10-11 mg/kg) [4], but comparable to Huhu grubs (7.1 to 8.9 mg/kg). Copper plays a role in redox reactions and, together with zinc, are important co-factors of the antioxidant enzyme superoxide dismutase [62].