Towards sustainable integration of edible insects as nutrient

rich resources in South-eastern regions of Zimbabwe

Musundire Robert

Department of Crop Science & Postharvest Technology

Chinhoyi University of Technology, Zimbabwe

In this presentation!

• Overview of agricultural activities and circumstances in the SE regions of

Zimbabwe

• Observations on cultural practices associated with edible insects

consumption

• How I became to study edible insects?

• Important research/ scientific gaps and summary of research activities

• Major research findings in studies with selected edible insects

• Current activities and research partnerships

• Road map for integrating insects as food

• Conclusions

Introduction/ Background

• annual rainfall < than 800mm

• low fertile soils

• frequent droughts

Source: www.wikipedia.org

Introduction/ Background

• most households harvest only between 0.5 to 1.5 tonnes of

cereals/ha

• many communities require food aid annually

Important Observations on Agriculture

1. Crop production is mainly rain-fed

2. Small grains are major cereal crops (millet, sorghum & finger millet)

3. Plants are major sources of proteins supplemented by meat from

small livestock & insects

4. Vegetables are abundant during summer season

5. Lean periods occur during prolonged dry periods (June to November).

Abundance of Edible Insects

In traditional practices and customs, communities in these districts consume:

• > 40 edible insect species

What captured my research interests on edible insects ????

• Insect consumer since childhood

• Interesting observations on cultural practices

Scientific gaps on Edible insects

1. Most edible insects are gathered from the wild are not well

documented and identified scientifically

2. Few studies on captive mass breeding of insects

3. Lack of data on effects of agricultural practices such as tillage &

pesticide applications on biodiversity

4. Contribution of edible insects to household food security not well

documented

5. Nutritional composition of most edible insects not available

6. Effects of cultural practices on quality & safety not studied for most

insects

7. Lack of data insect and habitat changes due to prolonged harvesting

8. Lack of structured policies on stewardship of entomophagy

Scientific gaps on Edible insects (ctd)

Scientific gaps on Edible insects

9. Studies on structural organization of edible insect harvesting,

utilization and consumption is lacking

Highlights of Research Findings

Main aims of research studies

1. To establish nutritional values (proximate constituent s) of edible insect

species in SE regions of Zimbabwe

2. To gather indigenous knowledge from communities on utilization &

consumption of edible insects

3. To determine effect of insect harvesting & processing on quality & safety

4. To document host plant and habitats for edible insects

5. To establish the level of stewardship on entomophagy

Materials and Methods- Nutritional composition- sample collection sites

9 species studied

1. Brachytrupes

membranaceus

2. Eulopida mashona

3. Encosternum

delegorguei

4. Gonanisa maia

5. Gonimbrasia belina

6. Gryllotalpa africana

7. Loba leopardina

8. Macrotermes

natalensis

9. Ornithacris turbida

Results- Nutritional composition

Insect species Constituent

Protein Fat Ash Carbohydrate fibre Energy

(kcal/100g)

Brachytrupes membranaceus 53.4 15.8 6.0 15.1 5.0 454.7

Encosternum delegorguei (well prepared)

(edible stink bug)

43.3 45 1.3 5.0 5.3 597.4

Encosternum delegorguei (spoiled) 31.6 38.9 3.8 3.7 22.0 490.4

Eulopida mashona (ground dwelling larvae) 46.3 11.8 10.9 16.2 14.8 352.2

Gonimbrasia belina (mopane worm) 55.4 16.4 8.3 8.2 16 329.1

Gonanisa maia 51.1 10.9 7.7 14.1 16.2 355.3

Gryllotalpa africana (Field cricket) 22.0 10.8 12.6 47.2 7.4 362.3

Loba leopardina (Chinhoyi) (cicada) 26.0 12.1 7.6 39.3 15.0 360.5

Loba leopardina (Negwari) 25.81 12.6 6.6 40.2 14.7 367.5

Macrotermes natalensis (reproductives) 37.1 41.6 3.5 0.4 4.9 542.5

Ornithacris turbida (grasshopper) 42.7 29.4 4.5 18.2 2.0 503.9

Henicus whellani 53.58 4.33 13.4 4.0±0.58 10.6 268.3±1.

• species variations in the nutrient composition

(recommendations on dietary intake of insects should be based on

extensive studies that investigate effect of insect diet and habitats on

their nutritional composition of insects)

• indications are that ground dwelling insects have higher ash content and

thus likely to have higher mineral content

• Processing methods seemed to have a significant influence on nutritional

composition

Conclusions and highlights

Study series 2: To determine effect of insect harvesting & processing on

quality & safety

Specific objectives

i) To determine effect of processing on phytochemical composition

ii) To determine effect of cooking duration on levels of anti-nutritional

compounds

iii) To establish the level of mycotoxin contamination due to traditional insect

processing practices

Materials & Methods

Analyte Method used Reference

Proximate composition

analyses

Crude: protein, fat, fibre

Ash

Moisture

Carbohydrates

Pearson 1981

AOAC 1990

Cardiac glycosides i) Kedde’s test Harborne 1973

Sofawara 1993

Oxalates Titration Amoo & Agunbiade2010

Phytates Colorimetric Vaintraub&Laptewa 1988

Materials & Methods (ctd)

Analyte Method used Reference

Alkaloids Gravimetric Harbone 1973

Total phenolics spectrophotometric Panarrieta et al. 2007

Tannins spectrophotometric Price et al. 1978

Steroids & Terpenoids i) Libermann-Buchard

Test

ii) Salkowski Test

De et al. 2010

Edeoga et al. 2005

Flavonoids Alkaline reagent test &

spectrophotometric

De et al. 2010

Jimo et al. 2010

Anthraquinones i) Borntrager’s Test

ii) Modified Borntrager

De et al. 2010

Materials & Methods (ctd)

Analyte Method used Reference

Saponins Vanillin- sulphuric acid

method

Hiai et al. 1976

Cyanogen glycosides Quantified as total

cynanide

Makkah 2003

Bioassays for Radical scavenging activity

% DPPH Absorbance Sharma et al. 2011

Results (Phytochemical composition)

Analyte Soldier termites Monster crickets

Oxalates (g/100g) 14.08 ± 0.6 9.31 ± 0.43

Phytates Not detected Not detected

Cyanogen glycosides (µg/100g) Not detected Not detected

Alkaloids (g/100g) 7.4 ± 0.6 5.2 ± 0.2

Total phenolics (mg /100g) 9.37 ± 0.79 7.77 ± 0.46

Tannins e (mg/100g) 0.02 ± 0.004 0.17 ± 0.007

Flavonoids (g CE/100g) 15.14 ± 0.64 15.50 ± 0.94

Table 2: Phytochemical composition of raw Monster Cricke and Soldier termites

Key: *CE- Catechin equivalents *GAE – Gallic acid equivalents

Results (ctd)

DPPH radical scavenging activity of methanolic extracts of Soldier termites (M.

natalensis) & Monster crickets (H. whellani) Anti-oxidant properties

Sample % DPPH Radical scavenging activity

Ascorbic acid 97 + 1

BHA 97 + 1

Termites (M. natalensis) 94 + 3

Monster crickets (H. whellani) 42 + 6

E. mashona 55 ± 4

E. delegorguei (raw) 88 ± 3

E. delegorguei (processed) 78 ± 7

Discussions & Highlights

i) Flavonoids were present in apprciable quantities in species where

degutting is not done

ii) Soldier termites’ extracts have potential high anti-oxidant

properties

iii) Edible stink bugs had high levels of Tridicane if not properly

processed

Improper processing results in accumulation of pheromone and

spoilage

Results

Protein (%) Fat (%) Ash (%) Carbohydrate

(%)

Crude

fibre (%)

Moisture

(%)

Energy

(Kcal/g)

Well Prepared (our sample)

23.58 24.53 0.71 2.75 2.9 45.53 325.40

Spoiled (our sample)

21.09 25.93 2.53 2.49 14.66 33.3 327.07

Table 1: Partial chemical compostion of E. delegorguei (Edible stink bug)

Introduction

• Previous chemical analytical research on edible stinkbug:

• basic nutritional composition

Emerging research dimensions include:

• bioactive compound composition

• risk assessment of consumed insects (mycotoxins &

antinutrients)

Introduction

Burning off the harmful pheromone

Storage of properly processed insects

Storage of properly processed insects

$$

Introduction

Unprocessed bugs Processed bugs

Traditional methods of collecting & storing bugs

Objectives

• to assess effect of E. delegorguei traditional harvesting

& processing practices on:

• levels of aflatoxins

• composition of fatty acids

• compostion of flavonoids

Materials & Methods

Analyses of flavonoids:

• traditionally processed and unprocessed samples

tested (Ferreres et al. 2003)

• analyses were performed using LC-MS &

confirmed with authentic standards

Table 1. Composition of Aflatoxins found on processed &

unprocessed bugs

Results

Aflatoxin group Processed bugs Unprocessed

bugs

B1 √ √

B2 complex − −

Gcomplex − −

M complex − −

Quantities of Aflatoxin B1 (ng) per g of insect materialR

elat

ive

quan

tity

(ng

)

Processed Unprocessed

Results (cntd)

Fatty acids in Encosternum delegorgue (mg/g) of insect materialR

elat

ive

qu

anti

ty m

g/g

Results (cntd)

0

2

4

6

8

10

12

14

16

18

20

Methylpalmitoleate

MethylOleate

(DEHA) Methylpalmitate

Methyllinoleate

Methylstearate

Processed

Unprocessed

•Anti-oxidant properties

DPPH Radical scavenging activities of insect extracts

Insect % DPPH radical scavenging activity

Termites 94 ± 3

H. whelani 42 ± 6

E. mashona 55 ± 4

E. delegorguei (raw) 88 ± 3

E. delegorguei (processed) 78 ± 7

Ascorbic acid 92 ± 1

BHA 97 ± 1

Catechin 92 ± 3

•Anti-oxidant properties

DPPH Radical scavenging activities of insect extracts

Composition of flavonoids in insect material

Results (cntd)

Type of

Flavonoid

Processed bugs Unprocessed

bugs

Apigenin √ √

Luteolin √ √

Quercitin √ √

Rutin √ √

Vetexin − −

Discussions & Highlights

i) Aflatoxin B1 associated with edible bugs

ii) Essential fatty acids: processed > unprocessed insects

iii) Flavonoids: processed < unprocessed insects

Conclusions

• presence of aflatoxin B1 is associated with traditional

insect harvesting, processing and storage practices

• Edible bugs are a good source of Essential fatty acids

• quantities of flavonoids could be affected by the

traditional processing method

Effect of cooking duration on levels of anti-nutritional

compounds

Secrets of insects menu preparation

Insects are

poisonous

when

consumed by

human males

• Mass rearing experiments with promising edible insects

• Formation of Multi-disciplinary teams & Edible Insects Research

group

• Nutritionists, Medics, Social Scientists & Biochemists

• Product formulation (food and feed)

• Advocacy

• Advocate for enterprises based on trade in edible insects (Value chain

studies???? Volunteers????)

Where we are going!!!!

Discussions & Highlights

i) Flavonoids were present in apprciable quantities in species where

degutting is not done

ii) Soldier termites’ extracts have potential high anti-oxidant

properties

iii) Edible stink bugs had high levels of Tridicane if not properly

processed

Acknowledgements

i) ICIPE

ii) DAAD (German Academic Exchange Programme)

iii) Swedish International Development Agency (Sida)

iv) AgriFoSe 2030

v) Chinhoyi University of Technology

vi) Swedish University of Agricultural Sciences

Acknowledgements

THE END