scholarly journals The nitrogen-to-protein conversion factor of two cricket species - Acheta domesticus and Gryllus bimaculatus

2020 ◽  
Vol 29 (1) ◽  
Author(s):  
Tiina Ritvanen ◽  
Helena Pastell ◽  
Annikki Welling ◽  
Marja Raatikainen

The Kjeldahl method is the most utilized method for total protein content analysis in food. Using the universal nitrogen-to-protein conversion factor of 6.25, the protein content of insects is likely to be overestimated due to their chitin content. We have calculated nitrogen-to-protein conversion factors for two crickets, house cricket (Acheta domesticus) and field cricket (Gryllus bimaculatus), which are used for food and feed in Europe. By analyzing their nitrogen and amino acid content we were able to show that a conversion factor of 5.09 could be used for house cricket and 5.00 for field cricket in protein content calculation. Based on these results with a reservation about slight variation in farming conditions, we suggest a nitrogen conversion factor of 5.0 for both crickets.

1992 ◽  
Vol 75 (4) ◽  
pp. 734-737 ◽  
Author(s):  
Shahrokh Khanizadeh ◽  
Deborah Buszard ◽  
Constantinos G Zarkadas

Abstract Three methods (Kjeldahl, sulfuric acid-hydrogen peroxide, and summation of amino acid content) for determining and calculating the protein content of apple flower buds were compared. Quantitation of protein content based on summation of amino acids appears to be the most accurate method. A new nitrogen:protein conversion factor (5.51) was calculated based on total amino acid analysis. This new conversion factor could replace the conventional 6.25 factor for estimating total protein content of apple flower bud by the Kjeldahl method. However, Kjeldahl is not an accurate method for estimating protein content in apple flower bud tissue, regardless of the conversion factor, and probably would not be a good method for estimation of protein in other plant species.


2019 ◽  
Vol 25 (4) ◽  
pp. 597-605 ◽  
Author(s):  
Natteewan Udomsil ◽  
Sumeth Imsoonthornruksa ◽  
Chotika Gosalawit ◽  
Mariena Ketudat-Cairns

2003 ◽  
Vol 83 (2) ◽  
pp. 409-410 ◽  
Author(s):  
T. S. C. Li ◽  
D. Wardle

A study was conducted at Summerland, BC, in 2000 and 2001 to investigate the effect of harvest period on the protein content of sea buckthorn leaves. Leaves of both male and female plants were collected bi-weekly during the growing season and analyzed with a LECO FP-528 nitrogen analyzer after air- and freeze-drying. A conversion factor of kA = 5.7 was applied to obtain the protein content. Total protein content in sea buckthorn leaves showed very small differences between male and female plants and from either freeze-dried or air-dried materials. There were significant fluctuations among harvest periods in both years. Based on the results of this experiment, sea buckthorn leaves should be harvested from late July to early August since leaf protein content peaked around this period of time and started to decline significantly by the middle of August. Key words: Sea buckthorn, Hippophae rhamnoides L., leaf protein


2021 ◽  
pp. 1-14
Author(s):  
L. Ribeiro ◽  
L.M. Cunha ◽  
P. García-Segovia ◽  
J. Martínez-Monzó ◽  
M. Igual

The demand for healthy, satiating, and convenient products is growing, with ready-to-eat expanded snacks being the preferred. These are produced made by extrusion, which is a versatile and efficient technology, with an immense potential to develop new food products. In addition to satisfy consumer requests, it is interesting to add alternative protein sources to these products, such as insects that have nutritional benefits and ecological advantages. The aim of this work is to evaluate the effect of extrusion temperature and enrichment with house cricket (Acheta domesticus) on properties of extruded snacks. Extrudates were produced with a single-screw extruder at two barrel temperatures (165 and 175 °C), formulated with corn flour and house cricket powder in mass ratios, 100:0, 95:5, 90:10, and 85:15. Water content, water activity, expansion, porosity, water absorption, water solubility indices; swelling index and hygroscopicity; colour, texture, protein content, in vitro digestibility, and protein bioaccessibility were measured. The results suggest that incorporating edible insects in extruded snacks can be a good alternative to the snacks on the market, since they maintain the appropriate physicochemical characteristics, especially when formulated at low temperatures. Further, they improve the protein content, with the recommended percentage use of 5 and 10% of house cricket, for the formulation of snacks with extrusion at 165 °C.


1995 ◽  
Vol 198 (5) ◽  
pp. 1071-1077 ◽  
Author(s):  
T Gomi ◽  
T Okuda ◽  
S Tanaka

The development and degeneration of the flight muscles in adult crickets, Gryllus bimaculatus, were studied (1) by determination of the total protein content, (2) by SDS one-dimensional polyacrylamide gel electrophoresis (SDS­PAGE) of muscle protein and (3) by in vitro culturing of the muscle. The total protein content of the dorso-longitudinal muscle (DLM) and metathoracic dorso-ventral muscle (DVM) increased during the early days of adult life in both sexes. This high protein content was maintained for at least a further 10 days in some individuals, while in others it declined to a low level. Mesothoracic DVMs in males also showed an increase in protein content after adult emergence but did not undergo histolysis, whereas those in females showed no significant temporal change in protein content. Removal of hind wings or artificial de-alation was found to be useful in inducing degeneration of DLMs and metathoracic DVMs. This treatment also stimulated ovarian development in females. An analysis by SDS­PAGE provided no evidence for new protein synthesis prior to or during flight muscle degeneration. A high rate of [3H]- or [35S]methionine incorporation was observed in DLMs taken from newly emerged adults, but, in intact crickets, the rate declined rapidly during the first 3 days of adult life, a pattern consistent with that obtained from the measurement of total protein content. Compared with DLMs removed from intact crickets, DLMs taken from de-alated crickets showed reduced rates of protein synthesis during in vitro culturing. This, together with the onset of protein degradation, appears to cause the rapid decrease in total protein content of the muscle in de-alated crickets.


Foods ◽  
2019 ◽  
Vol 8 (9) ◽  
pp. 400 ◽  
Author(s):  
Messina ◽  
Gaglio ◽  
Morghese ◽  
Tolone ◽  
Arena ◽  
...  

Microbiological, nutritional and bioactive properties of edible powders obtained from Acheta domesticus (house cricket) and Tenebrio molitor (mealworm) were investigated. Except for the enterobacteria, viable bacteria were at a higher concentration in mealworm flour. The diversity evaluation carried out using MiSeq Illumina that mainly identified Citrobacter and Enterobacteriaceae in mealworm powder and members of the Porphyromonadaceae family in house cricket powder. Enterococci were identified and characterized for their safety characteristics in terms of the absence of antibiotic resistance and virulence. Both powders represent a good source of proteins and lipids. The fatty acid profile of mealworm powder was characterized by the predominance of the monounsaturated fatty acids and house cricket powder by saturated fatty acids. The enzymatic hydrolysis produced the best results in terms of percentage of degree of hydrolysis with the enzyme Alcalase, and these data were confirmed by SDS-PAGE electrophoresis. Furthermore, the results showed that the protein hydrolysate of these powders produces a significant antioxidant power.


Botany ◽  
2020 ◽  
Vol 98 (3) ◽  
pp. 137-146 ◽  
Author(s):  
Qingfen Zhang ◽  
Dongmei Qi ◽  
Xiaobing Dong ◽  
Xiaoxia Li ◽  
Liqin Cheng ◽  
...  

The protein content of plants is commonly estimated by multiplying the total nitrogen content (Kjeldahl; KN) by a nitrogen-to-protein conversion factor of 6.25. This method is based on the incorrect assumption that all nitrogen in the ammonia/ammonium and organic substances in plants is protein nitrogen, usually resulting in overestimation of protein content. We have examined amino acid composition, amino acid nitrogen, total nitrogen (KN), and actual protein content (AP) determined from amino acid residues in 16 accessions of perennial sheepgrass (Leymus chinensis (Trin.) Tzvelev). We determined a new nitrogen-to-protein conversion factor, kP, as the ratio of AP to KN, and applied this factor to estimate the total protein content (TP) as KN × kP. The non-protein nitrogen accounted for 40.5% to 62.4% of the total nitrogen. The average kP value was 3.17 overall, 3.20 in the accessions sampled at the jointing stage, and 3.15 in the accessions sampled at the flowering stage. The TP, calculated as KN × 3.17, was about half that of crude protein contents, calculated as KN × 6.25. Our study suggests that the AP-based kP of 3.17 can be used to more accurately estimate the total protein content in sheepgrass.


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