Introduction

Monosodium glutamate (MSG), also known as Sodium glutamate and MSG, is a sodium salt of the naturally occurring non-essential amino acid, glutamic acid. It is used as a food additive and is commonly marketed as a flavour enhancer. Trade names of monosodium glutamate include Ajinomoto, Vedan, and Accent. It was once predominantly made from wheat gluten, but is now mostly made from bacterial fermentation. It is acceptable for celiacs following a gluten-free diet¹. Although traditional Asian cuisine had often used seaweed extract, which contains high concentrations of glutamic acid, MSG was not isolated until 1907 by Kikunea Ikeda. From 1909 to the mid 1960s, MSG was prepared by the hydrolysis of wheat gluten, which is roughly 25% glutamic acid. Glutamic acid is one of the least soluble amino acids, which facilitates its purification², MSG was subsequently patented by Ajinomoto Corporation of Japan in 1909. It was introduced to the United States in 1947 as Ac'cent flavor enhancer³.

MSG is used commercially as a flavour enhancer, although once associated with foods in Chinese restaurants, MSG is now used by most fast food chains and in many foodstuffs, particularly processed foods. Only the L-glutamate enantiomer has flavour-enhancing properties.^{4 MSG improves the palatability of meals and thus influences the appetite centre positively with it resultant increase in body weight5. Though MSG enhances appetite, reports indicate that it is toxic to human and experimental animals6. MSG has a toxic effect on the testis by causing a significant oligozoospermia and increase abnormal sperm morphology in a dose-dependent fashion in male Wistar rats7. It has been implicated in male infertility by causing testicular hemorrhage, degeneration and alteration of sperm cell population and morphology8. It has been reported that MSG has neurotoxic effects resulting in brain cell damage, retinal degeneration, endocrine disorder and some pathological conditions such as addition, stroke, epilepsy, brain trauma, neuropathic pain, schizophrenia, anxiety, depression, Parkinson's disease, Alzheimer's disease, Huntington's disease, and amyotrophic lateral sclerosis9,10.}

The safety of MSG's usage has generated much controversy locally and globally¹¹. There is a growing apprehension that its excellent bleaching properties could be harmful or injurious to the stomach mucosa, or worse still inducing terminal diseases in consumers when ingested as a flavor enhancer in food. Despite evidence of negative consumer response to MSG, reputable international organizations and nutritionist have continued to endorse MSG, reiterating that it has no adverse reactions in humans. Notably of such is the Directorate and Regulatory Affairs of Food and Drug Administration and Control (FDA&C) in Nigeria, now NAFDAC has also expressed the view that MSG is not injurious to health¹². In Nigeria, most communities and individuals often use MSG as a bleaching agent for the removal of stains from clothes¹³.

Hydrogen peroxide (H₂O₂) on the other hand is a very pale blue liquid, slightly more viscous than water, which appears colourless in dilute solution. It is a weak acid, has strong oxidizing properties, and is a powerful bleaching agent. It is used as a disinfectant, antiseptic, oxidizer, and in rocketry as a propellant.¹⁴ About 50% of the world's production of hydrogen peroxide in 1994 was used for pulp- and paper-bleaching¹⁵.Other bleaching applications are becoming more important as hydrogen peroxide is seen as an environmentally benign alternative to chlorine-based bleaches. It is highly corrosive to metal. Its oxidizing properties are used in the bleaching of substances, such as hair, ivory, feathers, bones and delicate fabrics, which would be destroyed by other agents. It is also used medicinally, in the form of a 3% aqueous solution, as an antiseptic and throat wash and its greatest activity is towards Gram-positive bacteria, but the presence of catalase in these bacteria makes dilutions below three percent less effective ¹⁶.

Bleaching of bones is necessary so as to make the bones whiter and more presentable. Historically this procedure has been performed since antiquity by using just sunlight as a bleaching agent, sunlight acts as a bleach through a process leading to similar results: high energy photons of light, often in the violet or ultraviolet range, can disrupt the bonds in the chromophore, rendering the resulting substance colorless. Extended exposure often leads to massive discoloration usually reducing the colors to white and typically very faded blue spectrums.¹⁷ but later due to the environmental dependence and time waste it was replaced by chemicals such as sodium hypochlorite although a bleaching agent is also used as a contaminant remover¹⁸.The most commonly accepted chemicals used for bleaching is hydrogen peroxide which is currently used today although report has it that it has effects on bone mineral matrix ratio¹⁹. With hydrogen peroxide the bone samples are immersed in 4%-35% hydrogen peroxide for 24 hours or few days depending on the concentration and temperature after which it is dried on an absorbing paper in open air²⁰.

The aim of this study is to compare the bleaching effects of MSG with the conventional hydrogen peroxide which is currently used to bleach bones. We figured out that if we carry out an experiment to compare the effect of MSG and hydrogen peroxide on bones, we might be able to replace hydrogen peroxide with MSG which is cheaper and easily available in other to be able to bleach bones easily at a more affordable price, for use in natural history museums, forensic laboratories and medical schools.

Materials and Method

Materials

Method

Observation/Result

It was observed that the bleaching of bones immersed in monosodium glutamate solution competed favorably well with those bleached with hydrogen peroxide solution, after it was immersed in both solutions and left on an absorbent paper to dry²⁰. These observations reveals that MSG, a commercial spice used for household cooking proved to be an effective bleaching agent in bone preparation. We also observed that MSG proved to be cost effective in view of its low cost and availability as compared to hydrogen peroxide which is very costly and not readily available in rural setting. The result of the experiment showed that MSG was able to bleach the bones and the effect competed favorably with hydrogen peroxide.

Figure 1

A TABLE SHOWING THE COMPARISM BETWEEN PRICES OF VARIOUS CHEMICALS USED

Pictures

Figure 2

CAPRINE SKULL BLEACHED WITH H2O2 [2HOURS OLD]

Figure 3

PORCINE SKULL BLEACHED WITH MSG [2 HOURS OLD]

Figure 4

PORCINE MANDIBLE BLEACHED WITH H2O2 [2 HOURS OLD]

Figure 5

CAPRINE MANDIBLE BLEACHED WITH MSG [2 HOURS OLD]

Figure 6

PORCINE SKULL BLEACHED WITH MSG (11/2 YEARS OLD)

Figure 7

CAPRINE SKULL BLEACHED WITH H2O2 (11/2 YEARS OLD)

Figure 8

CAPRINE MANDIBLE BLEACHED WITH MSG (11/2 YEARS OLD)

Figure 9

PORCINE MANDIBLE BLEACHED WITH H2O2 (11/2 YEARS OLD)

Figure 10

OTHER BONES SAMPLES BLEACHED WITH MSG

Discussion

It was observed that 120mg of monosodium glutamate costs only $0.33 while its hydrogen peroxide equivalent costs $20 so, hydrogen peroxide is not just only expensive but it is not readily available in rural settings like our university environment. Researches have also shown that MSG has a beaching effect not only on bones but also on clothing fabrics. It was then figured out that if more research is carried out in this aspect, MSG can be used to replace hydrogen peroxide which is more costly and less easily available moreover further researches has shown that hydrogen peroxide may have effect on the bone matrix¹⁹ Although MSG has also been showed to have effect on the medial geniculate body by causing cellular degenerative changes, autophagic vacuoles and neuronal hypertrophy¹³ and in the testis by causing cystic degeneration, vacuolations and degenerative and atrophic changes which is worse in the high dose²³, all the effects above can only manifest when ingested. If MSG can replace hydrogen peroxide it would be easier for people especially students to bleach bones whichever the settings they may find themselves at a very low cost without necessarily having a standard laboratory hence more specimen can easily be bleached. This will better equip our anatomical museums and could also be used for the preparation of small bones like the temporal bones for the purpose of display, exhibition or competition. The bone preparation methodology also has prosthetic implications²⁴.

Conclusion

Bone preparation for use in medical schools, natural history museums and in forensic analysis²⁵ can be made easier, cheaper and faster if readily available materials such as MSG can replace conventional chemicals such as hydrogen peroxide. The very high cost and unavailability of hydrogen peroxide in most parts of the country especially the rural university Community is also a drawback.