Effect of processing, packaging and storage-temperature based hurdles on the shelf stability of sautéed ready-to-eat Ruspolia nitidula

Abstract

Ruspolia nitidula (an edible grasshopper) is a seasonal delicacy in Uganda and its neighbouring countries, with a postharvest shelf stability of 1-2 days. Our previous processing research increased the shelf stability of ready-to-eat R. nitidula to 12 weeks at ambient temperature. However, there is need to double the shelf-life to cover the 20-24 weeks between swarming seasons and, increase the efficiency and cost effectiveness of the processing and packaging techniques developed. This research investigated the effectiveness of 9 preservation hurdles on the microbial (total plate count), sensorial (overall acceptability) and chemical (acid value, peroxide value and thio-barbituric acid value) stability of ready-to-eat R. nitidula. Chilled storage and ambient temperature storage of the vacuum packed product increased the shelf stability of R. nitidula from 12 to 22 weeks. After 22 weeks of storage, the products had an overall acceptability of 6-7 on a 9-point hedonic scale, a total plate count of <4 log cfu/g, an acid value of approximately <1 mg KOH/g, a peroxide value of <21.50 meq O2/kg and a thio-barbituric value of <0.079. Either chilled storage or vacuum packaging are suitable means of preserving dried ready-to-eat edible grass hoppers and can be used depending on availability. Further research into increasing the shelf stability of R. nitidula at room temperature will be very beneficial to its commercialisation.

Traditions, beliefs and indigenous technologies in connection with the edible longhorn grasshopper Ruspolia differens (Serville 1838) in Tanzania

“…Eating them raw was regarded unethical by most respondents who associate it with stomachache (52%) and diarrhoea (48%). There is scientific evidence that raw insects contain higher microbial counts, thus consuming them raw can bring such complications [ 20 ]. The remaining 8% had eaten fresh raw senene out of greed, although some apparently appreciated the raw senene.…”

Edible Insects Processing: Traditional and Innovative Technologies

“…When refrigeration is combined with vacuum or modified atmospheres, the shelf‐life of the products increases markedly. Storage under vacuum and darkness can improve the shelf‐life of whole edible insects even when stored at room temperature (Ssepuuya, Aringo, Mukisa, & Nakimbugwe, ). Vacuum packing improves the microbiological quality of the product, while darkness prevents lipid oxidation.…”

“…For instance, whole Ruspolia nitidula (a grasshopper), when pan‐fried and dried, maintained edible quality (sensory and microbiological) for 12 weeks. No significant difference in total plate counts was observed when vacuum (reduced pressure) was applied (Ssepuuya et al., ). In addition, vacuum storage can maintain the microbial (total plate count), sensory (overall acceptability), and chemical properties (acid value, peroxide value, and thiobarbituric acid values) of ready‐to‐eat R. nitidula for 22 weeks similarly to low‐temperature storage (Ssepuuya, Mukisa, & Nakimbugwe, ).…”

Postharvest processes of edible insects in Africa: A review of processing methods, and the implications for nutrition, safety and new products development

“…The interplay between molds, insects and microorganisms in the causation of physical damage, weight loss, odor development, chemical modification, and mycotoxin contamination hasten the postharvest deterioration of the caterpillars (Mpuchane et al, 2000). In Uganda, the shelf-stability of sautéed ready-to-eat edible grasshopper (Ruspolia nitidula) were investigated (Ssepuuya et al, 2016) with respect to different methods of processing, packaging and storage.…”

“…The postharvest shelf-life of fresh R. nitidula is 1--2 days. A preservation process involving sautéing (dry-pan frying), drying, and storage at room temperature in opaque vacuum package or transparent plastic container increased the shelf-life to 12 weeks (Ssepuuya et al, 2016). Chilled and frozen temperature storages of the vacuum or non-vacuum packed product increased the shelf-life of R. nitidula from 12 to 22 weeks; the products retained overall acceptability of 6--7 on a 9-point hedonic scale and a total plate count of <4 log cfu/g an acid value of <1 mg KOH/g, a peroxide value of < 21.5 meq O 2 /kg and a thio-barbituric value of <0.08.…”