By Eben van Tonder 28 January 2022
For several years now I have been looking into the use of the 5th quarter from animal slaughtering to find ways to use this more effectively in human nutrition. Despite legislative challenges which classify, for example, animal bones as inedible, thorough investigations have been carried out over the years which clearly show such legislation to be outdated and ill-informed. In other instances, it is due to mostly Western prejudice against the consumption of certain parts of the animal which made its way into legislation.
Some animal parts classified as in-edible in Western countries are customarily used in several non-Western countries as human food such as beef hides which is consumed in Nigeria as Ponmo (Kpomo). An attempt is being made in some Western countries to find a way past the outdated and ill-informed legislation by having such food classified as traditional dishes.
An even more surprising situation exists in a country like South Africa where it seems as if the authorities frown upon attempts to even investigate the use of these by-products in food processing. When they make their case, they do not refer to science, for example, to try and show that certain animal parts are harmful when consumed but to legislation in Western countries as if this is anything to go by. The unambiguous evidence of mounting research data is that consuming a great percentage of these so-called in-edible parts of a carcass is not dangerous to humans. On the contrary! It turns out to be highly nutritious and their inclusion in, for example, sausage formulations will add to the nutritional characteristics of the food and lower prices.
Over the last few years equipment has become available to process certain animal by-products in such a way that nutrition is enhanced by increased bioavailability, mostly through a greater degree of comminution. Disruptor technology has for example been pioneered in South Africa which reduce the particle size of these by-products dramatically. Ultrafine grinding of bones has become possible through a range of equipment and processes. The high-volume processing of such material will undoubtedly have to be done through equipment like the Dynamic Cellular Disruption (DCD) process, pioneered by Green Cell Technologies (GCT), but smaller machines for small processing are available.
This means that from the perspective of nutrition (backed up by thorough scientific research) and equipment, there is no longer any reason to maintain the archaic Western-focused aversion to the processing of the entire carcass and including most of it in food produced for human consumption should be legislated. In countries where bones and animal hides have not been classified as inedible, the status quo should remain unchanged for the benefit of the respective populations, culturally, nutritionally, and as far as affordability is concerned. From a philosophical perspective, it is my opinion that not utilising the full carcass for human nutrition shows great disrespect to the animal by somehow implying that certain parts are only good to feed other animals or fertiliser.
Animal Bones are Nutritious.
The first point that must be made about bones is that it is already part of human food in the form of broth and soups. If we just pause there and realise that in South Africa it’s classified as not fit for human consumption we can ask, so are we or are we not allowed to sell “meaty bones” (as is being done), as soup bones? So, the legislature allows it because this is an extremely popular South African product, despite being described, technically, as “not fit for human consumption.” So much so that the bones are no problem in South Africa and sell at such good prices that producers give bones not a second thought. The market exists for it by simply cutting it up with a bandsaw into smaller chunks.
Chicken bone is another example that is much softer than other animal bones and comes to us through MDM. In some countries in Africa, MDM is banned for no good technical reason and as far as Europe is concerned, it is a completely different reason which is beyond the scope of our current discussion.
Back to the South African example. We are allowed to sell all the bones in the entire country to be used in soups and we are allowed to use MDM which are packed with chicken bones, still using bone meal as is produced for animal feed around the world in food for human consumption will be a problem for the South African legislator.
These inconsistencies in handling the matter aside, the reality is that bones are packed with nutritional elements. The fat and protein content is, however, not parallel to that found in the rest of the body as some authors suggest. Paloheimo (1965) reported that the bone-free body of one of three Paloheimoof dairy cows analysed contained 25.2 % fat while the corresponding figure of the skeleton was 19.9. The second cow gave figures 15.5 and 22.0 respectively, and the third 14.7 and 19.0. They continued their study and analysed specific bones as opposed to the whole carcass bones as in the three dairy cows. The average percentage from the femurs of 20 cows and 4 young animals, where fat, protein and ash were directly determined and the water content was calculated as the difference, are as follows (ranges of variation given in brackets).
Fat 33.6 (26.9 – 38.9)
Protein 17.2 (15.0 – 21.6)
Ash 34.8 (33.0 – 33.9)
Water 14.4 (11.3 – 16.0)
Bones serve amongst others, as a reservoir of calcium and phosphate ions for the entire body. It is “composed of various types of cells and collagenous extracellular organic matrix, which is predominantly type I collagen (85–95%) called osteoid that becomes mineralised by the deposition of calcium hydroxyapatite. The non-collagenous constituents are composed of proteins and proteoglycans, which are specific to bone and the dental hard connective tissues.” (Mohamed, 2008)
Yessimbekov (2021) investigated the use of meat-bone paste to develop calcium-enriched liver pâté. They found that “the compositional analysis of pâté manufactured with meat-bone paste showed that the reformulation did not influence the content of moisture (~56%), fat (~28%), or protein (~11%) while producing a significant increase of ash and a decrease of carbohydrates in comparison with control pâtés. The higher amounts of minerals of bone-meat paste, including calcium (3080 mg/100 g), magnesium (2120 mg/100 g), phosphorous (2564 mg/100 g), and iron (7.30 mg/100 g), explained the higher amount of both ash and these minerals in the reformulated samples compared to the control samples.”
The total caloric value (~300 kcal/100 g) was unaffected by the addition of bone-meat paste. “The content of both essential and non-essential amino acids decreased with the inclusion of meat-bone paste, although this decrease was lower in essential (6280 mg/100 g in control vs. 5756 mg/100 g in samples with 25% of meat-bone paste) than in non-essential amino acids (6080 mg/100 g in control vs. 3590 mg/100 g in samples with 25% of meat-bone paste). This fact is due to several essential amino acids not showing differences between control and reformulated samples, while in non-essential amino acids, these differences were greater.” (Yessimbekov, 2021)
“The results of this study showed that meat-bone paste addition is a good strategy to produce liver pâté enriched in minerals and with minimum influence on the content of the other important nutrients. Therefore, these results can be used for the design of new liver pâté with an increased nutritional significance by using meat industry by-products. According to the balance of minerals, the use of 15% of meat-bone paste to reformulate liver pâté is the best strategy used in the present research.” They caution that “additional studies on the stability (during storage), shelf-life, and sensory acceptability of these reformulated pâtés should be carried out.” (Yessimbekov, 2021)
Kakimov (2017) states that “bones are rich in mineral elements (in particular, calcium, phosphorus, magnesium and iron), protein (collagen) and fatty substances. Bone consists of 13.8 – 44.4% water, 32 – 32.8% protein (collagen), 28.0 – 53.0% mineral elements and 1.3 – 26.9% fat. The most characteristic components of bone are mineral elements, represented by calcium carbonate and phosphoric acid, followed by various oxides (%) (CaO 52, MgO 1.2, P2O5 40.3, Na2O 1.1, K2O 0.2, Cl 0.1, F 0.1 and CO2 5.0). Cattle bones, which contain between 9 and 14 mg kg–1 calcium are a major source for calcium and phosphorous salts.” They quote Drake et al., that “bone is a useful calcium source for nutrition because bone particles are readily dissolved by gastric juices. Moreover, the use of mineral salts in the production of meat-based products enables enrichment of food with mineral supplements, particularly calcium, phosphorous, magnesium and other elements that can be helpful in preventing diseases associated with mineral deficiencies, such as osteoporosis”. (Kakimov, 2017)
They state that “meat-bone meal can provide a rich source of whole protein and is an especially rich source of the essential amino acid lysine, as well as mineral supplements. For human consumption, bone is typically used to prepare protein hydrolysates and mineral supplements, bone broth and bone fat.” (Kakimov, 2017)
Kakamov (2017) describes a superfine bone grinding processes beginning with “crushing the bone to 1-3 mm particles followed by ultra fine grinding to yield 50-100 mm particles can be used to make paste-like products that have a soft texture and are fully digestible by humans.” He notes that such pastes can be used for the production of food supplements and different meat products such as sausages, pates and semi-finished meat products. Moreover, since the meat-bone grinding process does not involve thermal treatments, the vitamin, mineral and protein content is preserved
Kakimov (2017) evaluated the meat-bone paste (MBP) as an ingredient for meat batter and its effect on physicochemical properties and amino acid composition. They developed five formulations, a control and “four meat batters with different amounts of MBP, 10% (MBP-10), 20% (MBP-20), 30% (MBP-30) and 40% (MBP-40), respectively. The active acidity (pH) of the formulations was determined by potentiometry. Samples were analyzed for water binding capacity (WBC) by exudation of moisture onto filter paper following the application of pressure. The amino acid composition was determined by liquid chromatography.” (Kakimov, 2017)
Bone Paste Preparation
Kakimov (2017) summarises current processing methods as usually involving “grinding and hydrolysis of the bones, followed by treatment with various chemical reagents.” He references Berdutina and Antipova et al. who “describes the preparation of protein hydrolysates from bone that included fermentation and acid hydrolysis.” “For a study on the production of protein supplements,” Kakimov (2017) references Kutcsakov et al. who describes “hydrolysis of meat-bone raw material by hydrochloric acid followed by sodium hydroxide neutralization, defatting and drying.”
Yessimbekov (2021) mentions that a patent has recently been granted on one such process. “A patent was granted by the Republic of Kazakhstan #2202 on 15 June 2017 for the method developed by Kakimov et al.. Bone grinding processing by this procedure allows obtaining a meat-bone paste which is free of hard bone particles; thus, it results in a product that is smooth and soft to the tongue of the consumer.” (Yessimbekov, 2021)
“Bones with meat tissue were washed with cold water and then crushed into 50 –70mm long fragments. Cutting bones into small pieces was done manually with an axe. The bone fragments were stored at -18oC to – 20oC before loading into the hopper of a crushing machine equipped with an 8mm diameter meat grinder plate. The bone was ground and crushed again using a 3mm meat grinder plate; water was then added to a 1:1 ratio (w/w). The mixture was frozen at -3oC to -5oC for 1 h and then ground using a micro-milling machine having rotational knives spaced at 0.50mm. The resulting meat-bone paste (MBP)
was used to prepare pâté meat batters.” (Yessimbekov, 2021)
Kakimov (2017), to study the meat-bone paste as an ingredient for meat batter and the effect on physicochemical properties and amino acid composition used bones with attached meat tissue and “washed [it] with cold water and then crushed [it] into 50-70 mm long fragments. The bone fragments were stored at 18-20°C before loading into the hopper of a crushing machine V2-FDB (Russia) equipped with an 8 mm diameter meat grinder plate. The bone was ground and crushed again using a 3 mm meat grinder plate, water was then added to a 1:1 ratio (w/w). The mixture was frozen at -3 – 5°C for 1 h and then ground using a Supermasscolloider MKZA-10-15 (Masuko Sangyo Co., Ltd, Kawaguchi, Japan) micromilling machine having rotational knives spaced at 0.5 mm. The resulting meat-bone paste (MBP) was used to prepare meat batters.”
The meat batter they prepared was done as follows. “Five meat batter formulations were prepared using varying amounts of MBP and prime and grade one beef from which all visible connective tissue was removed. The mixtures were then ground by passage through a meat grinder fitted first with an 8 mm plate and then a 5 mm plate. The basic composition of the meat batter was 50% prime beef, 35% grade one beef (together, a total of 85% beef), 10% ground boiled beans and 5% egg mélange. Then, MBP was substituted for the prime and grade one beef mixture at four amounts 10, 20, 30 and 40%, respectively. Meat batters were prepared in a mixer-cutter to which the minced meat, MBP, boiled beans, 2.5% sodium nitrite, egg mélange and water were added individually. All the ingredients were mixed and ground together for 5-10 min at 2-4°C. Salt was added to extract myofibrillar proteins, whereas egg mélange was included as an emulsifier to bind the meat batter components, as well as a source of unsaturated fatty acids and lecithin. For seasoning, peeled and minced garlic, granulated sugar, black or white pepper and coriander were added. Sodium nitrite was included as a preservative. After mixing, the meat batters were packed in polyethylene bags and stored at (-8°C).” (Kakimov, 2017)
The following table shows the composition of the different meat mixes.
Bone-Paste Particle Size
Yessimbekov (2021) reports that “as can be seen in the image of bone particles, magnified 50 times where the bone particle sizes were measured, particle sizes exceeding 0.40 mm (400 microns) were not detected.
Bone particle sizes of meat-bone paste by Yessimbekov (2021).
“On the basis of the sieve analysis of the meat-bone paste after grinding on a colloid machine with a gap between the grinding wheels of 0.10 mm, it was found that the mass fraction of bone particles ranging in size from 0.10 mm to 0.25 mm is more than 95%. Bone particles that were beyond 0.25 mm were less than 5% and, as mentioned, particles of 0.40 mm (or higher) were not detected. Similar findings were obtained in a previous study, in which the meat-bone particle size after grinding on the colloid mincing machine was from 0.20 to 1.5 mm, while after grinding on the superfine machine, the particle size was reduced to less than 0.10 mm. A more recent study concluded that after grinding in the masscolloider with a gap of 0.25 mm, the bone particle size ranged between 0.14 mm and 0.37 mm, while after using a masscolloider with a gap of 0.10 mm, the bone size decreased and ranged between 0.045 mm and 0.19 mm. These results agree with our findings, and they demonstrate that the process and conditions for obtaining the meat-bone paste are good and that this allows obtaining a meat-bone paste with a smooth texture, which is not perceptible by consumers, and which is digestible by humans. Therefore, the meat-bone paste obtained in this research can be used for the production or reformulation of meat products: in our case, liver pâté.” (Yessimbekov, 2021)
Results from Kakimov Meat-Bone Batters
“Proximate composition of the meat-bone paste (MBP) was determined. Relative to the base formulation (control), MBP had a higher ash level (15.99±0.18%) but a lower fat (4.35±0.06%) and protein (14.70±0.17%) content and a moisture level of 64.97±0.79%. The effect of increasing amounts of MBP on the proximate composition of meat batters (table above) was analyzed. At 40% MBP (MBP-40), the ash content significantly increased relative to the control (5.24 vs. 0.81%), whereas the protein and fat content steadily decreased with increasing amounts of MBP. In particular, the fat content of the control sample fat content was 16.50% but the MBP-40 batter had only 10.71% fat. Meanwhile, MBP-40 had a lower protein content than the control, which was slightly but not significantly, lower than that of MBP-10 (16.26, 17.49 and 17.67%, respectively). The moisture content of the samples ranged from 65.20 – 67.79% and there were no significant differences among the formulations. The energy value of meat batters steadily decreased with the addition of MBP, with MBP-40 having the fewest calories per 100 g.” (Kakimov, 2017)
“The ash content of the MBP-30 and MBP-40 formulations was markedly higher (4.18 and 5.24%, respectively) than the recommended amount for meat batters (approximately 3.5%). Similar trends in moisture, fat and protein (64.17, 17.83, 16.68%, respectively) content were observed in a study by Kahramanov for meat batters made from grade two beef, fermented meat trimmings and blood. Except for the ash content, the proximate composition of these meat batters was also similar to that observed by Kakimov, who developed a protein supplement (protein 15.39%, fat 12.94% and ash 1.41%) for meat batters consisting of bone fat, blood, egg mélange and ultrafine ground bone. In another study, Pershina showed that bone powder added to a sausage formulation that included beef, pork, milk and eggs resulted in sausages that had a lower protein content (12.0-14.0%) and higher fat content (18-22%), which both differed from those seen for this study. Krishnan and Sharma used offal meat (rumen and heart meat) to process cooked sausages that had a protein content similar to the MBP-40 formulation (16.39% vs. 16.26%), whereas meat patties composed of ground beef and 10% spleen tissue in a study by Bittel and Graham had significantly higher protein content (26%) than it was seen with our formulations. Overall, however, the proximate composition of the meat batter was consistent with that observed for previous studies.” (Kakimov, 2017)
WBC and pH Determination:
“The pH is an important parameter that can significantly impact sensory, microbiological, physicochemical and rheological characteristics of meat and meat products. The addition of MBP raised the pH of the meat batter, with more neutral pH values seen for MBP-40 vs. the control (6.20 vs. 7.26). This effect is likely because the MBP itself has a high pH (7.28). The WBC also changed with the addition of increasing amounts of MBP as evidenced by the sharp and significant increase in WBC of more than 15% between MBP-10 and MBP-20. The increase can be attributed to the high water binding capacity of MBP.” (Kakimov, 2017)
WBC and pHin meat batter with different proportions of meat-bone paste. (Kakimov, 2017)
Amino Acid Determination
“The MBP also changed the total amino acid content of the meat batter formulation. Amino acid composition of MBP showed the large amount of glycine (2556.28 mg/100 g), proline (1649.32 mg/100 g) and oxyproline (1360.75 mg/100 g).” (Kakimov, 2017)
“These amino acids constitute the major portion of collagen and play an important role in human body. With increasing amounts of MBP, the amino acid content of the meat batters decreased, whereas the formulation with the lowest amount of MBP, MBP-10, was statistically similar to that of the control (21.0 g/100 g vs. 21.1 g/100 g). The amount of non-essential amino acids such as glycine and proline were significantly increased by approximately 43 and 21%, respectively, in meat batters with 40% MBP.” (Kakimov, 2017)
“Notably, these two amino acids, along with the proline derivative oxyproline are the major constituents of collagen and have an important physiological role in that glycine participates in nitrogen metabolism and protein synthesis and also has a vital role in brain function. Meanwhile, proline is essential for muscle stamina, as proline deficiencies are associated with fatigue.” (Kakimov, 2017)
“Consumption of foods with high amino acid contents that can be used for collagen production will contribute to muscle development and regeneration. Overall, the essential amino acid content of meat batters prepared here conformed to the Food and Agriculture Organization of the United Nations (FAO) scale for ideal protein content (table above). However, in MBP-40 meat batters, the limiting amino acids were methionine and cysteine (amino acid score 97.3%) and tryptophan (AS 98.4%). Methionine is a major building block for proteins and is associated with vitamin B12 deficiency. Tryptophan boosts synthesis of the vitamin PP and deficiencies in this amino acid can lead to serious illnesses such as tuberculosis, cancer and diabetes.” (Kakimov, 2017)
“The highest amino acid score was seen for meat batters with 10% MBP. Increases in the amount of MBP were associated with decreasing amino acid scores (Table above). The highest amino acid score was calculated for lysine (175.96) in MBP-10 and this value decreased to 149.04 for MBP-40. Lysine is essential for bone formation and childhood development and also promotes calcium digestion and nitrogen metabolism in humans. Moreover, adequate lysine is critical for synthesis of antibodies and hormones as well as for collagen formation and tissue regeneration. The sum of the phenylalanine and tyrosine content for the control was around 50% higher than the FAO recommendation and the addition of MBP upto 40% decreased the value to a level that was closer to that of the FAO (Table Above).” (Kakimov, 2017)
“The approximate level of leucine and threonine in both the formation and the controls was higher than that of the FAO, although MBP-40 had the lowest amount. The MBP-40 also had the lowest amount of isoleucine relative to the control and was closest to the value set by the FAO (4.44 vs. 4.0). Isoleucine is essential for hemoglobin production and provides an energy source for muscle while also preventing early muscle fatigue. Threonine improves cardiovascular and immune system function and that of the liver. This amino acid is also involved in glycine and serine synthesis. Each of these amino acids is important for strengthening ligaments and all muscles, including the heart.” (Kakimov, 2017)
“Overall, these results indicate that the optimum quantity of MBP in meat batters ranges between 10 and 20% of total mass. Partial replacement of beef with a MBP can reduce production costs by as much as 15% while enriching meat batters with amino acids such as glycine, proline and oxyproline. However, excess amounts of MBP in meat batter formulations reduces their nutritive value and is inconsistent with regulations for meat products.” (Kakimov, 2017)
These results are highly significant and show the scientific basis for the inclusion of bone meal in products intended for human consumption. We reviewed equipment available for producing bone meal. The Kakimov study is key in understanding the probably/ optimal range for inclusion of bone meal in fine emulsion meat products.
As far as equipment is concerned, this validates the work of Green Cell Technologies and their Dynamic Cell Disruption Technology which can accomplish what smaller equipment can do at a far increased rate and efficiency. They have demonstrated their equipment is able to reduce particle size of bones smaller and more effectively than other technology and since comminution of meat particles is tightly related to digestibility through greater bio availability (Notes on Comminution and Digestibility) for large plants this must remain their number one consideration. In many western countries, its inclusion in human food will remain problematic till legislative reforms are affected. Until such time, as far as bone meal is concerned, such technology’s main area of application will remain directed to the animal feed industry. Countries with greater sanity in legislation will have the opportunity to exploit technology like this to the direct benefit of their citizens through its inclusion into food for human consumption.
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Kakimov, A., Suychinov, A., Mayorov, A., Yessimbekov, Z., Okuskhanova, E., Kuderinova, N., and Bakiyeva, A.. (2017) Meat-bone Paste as an Ingredient for Meat Batter, Effect on Physicochemical Properties and Amino Acid Composition
Mohamed A. M. (2008). An overview of bone cells and their regulating factors of differentiation. The Malaysian journal of medical sciences : MJMS, 15(1), 4–12.
Paloheimo, L., Björkenheim, L. M., Leivonen, H.. (1965) STUDIES ON THE MAIN CHEMICAL COMPOSITION OF BONES, Department of Animal Husbandry, University of Helsinki, Journal.fi, Received January 2, 1965
Yessimbekov, Z., Kakimov, A., Caporaso, N., Suychinov, A., Kabdylzhar, B., Shariati, M. A., Baikadamova, A., Domínguez, R., Lorenzo, J. M.. 2021. Use of Meat-Bone Paste to Develop Calcium-Enriched Liver Pâté. Foods 2021, 10, 2042. https://doi.org/10.3390/foods10092042
All photos from https://www.istockphoto.com/search/2/image?phrase=roasted%20bone%20marrow&page=2