**1. Introduction**

Bamboo is regarded as a natural and renewable bioresource, a green and environmentally friendly material, and has chemical and physical qualities/properties similar to wood. It quickly reaches its full potential size, which usually only takes approximately 60–70 days after the bamboo culms emerge from the ground [1]. According to the annual statistics of the agricultural reports in Taiwan (2015), the volume of diverse bamboos is about 1,581,330,000 pieces. The three main types of bamboo used include *Phyllostachys makinoi* Hayata (Makino

Attribution License (http://creativecommons.org/licenses/by/3.0), which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited. © 2018 The Author(s). Licensee IntechOpen. This chapter is distributed under the terms of the Creative Commons Attribution License (http://creativecommons.org/licenses/by/3.0), which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.

© 2016 The Author(s). Licensee InTech. This chapter is distributed under the terms of the Creative Commons

bamboo), *Phyllostachys heterocycla* Milf (Moso bamboo), and *Dendrocalamus latiflorus* Munro (Ma bamboo) [2]. This indicates that bamboo is one of the economic green resources in Taiwan. Among these bamboos, Moso bamboo has been mainly used as a material for the making of furniture, handicrafts, and athletic/leisure goods, because it can grow over 20 m tall and 60–150 mm in diameter in one growing season [3]. Moreover, bamboo is accumulated from organic compounds from which a bamboo converts carbon dioxide (CO<sup>2</sup> ) by photosynthesis, but it can naturally decay by organic compound oxidization or be burned, and this produces CO<sup>2</sup> that returns to the atmosphere. To decrease bamboo decaying or burning, the preparation of charcoal becomes one of the selected methods because carbon can extend the lifetime of bamboo [4]. In other words, the charcoals can also become earth friendly materials because they can slow down the increase of CO<sup>2</sup> concentration in the atmosphere.

in Taiwan. However, bamboo vinegars collect at the exit of chimney of earthen or furnace kiln, when the carbonization temperature of bamboo is raised to over 500°C, produce some carcinogenic polycyclic aromatic hydrocarbons (PAHs), such as naphthalene and phenanthrene [28–30]. The concentrations of these toxics increase with the increase in temperature as well. Even though the council of agriculture in Taiwan has submitted certified agricultural standards of forest products (2004) to prove that it is necessary for bamboo vinegars to be collected at 80–150°C at an exit of chimney of earthen kiln and below 350°C for a furnace kiln [31], the collected bamboo vinegars from above this range of temperatures are necessary to evaluate the potential of mutagenic and carcinogenic agents, due to the fact that they are omnipresent in the human environment and seem impossible to completely eliminate.

Preliminary Safety Evaluation of Bamboo Pyrolysis Products: Charcoal and Vinegar

http://dx.doi.org/10.5772/intechopen.68542

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Ames *et al*. [32] reports that for screening of environmental mutagens and carcinogens, the Ames test (safety evaluation), a convenient method to evaluate mutagenic activities of these chemicals, has been developed, and McCann *et al*. and Sugimura *et al*. have suggested that the mutagenic activities of a number of chemicals correlate well with the carcinogenic activities [33, 34]. The main goal of this chapter is to realize fundamental knowledge of the bamboo charcoal/vinegars as functional additives, while at the same time understanding the preliminary safety evaluation of both using the bacterial mutation assay on *Salmonella typhimurium* (*S. typhimurium*) TA98 and TA100 strains with and without an extrinsic metabolic activation system. Moreover, because the reverse mutation assay (antimutagenic activity) has an array of prospective applications in human care, such as the increasing application in drinks and food antioxidation, and has not been reported for the antimutagenic activities of bamboo vinegars that have been made so far, the antimutagenic activity of the vinegars is reported. Besides, the basic compounds of vinegars, collected at different temperatures from the exit of earthen kiln chimney and analyzed by using gas chromatography-mass spectroscopy, are considered, in order to realized the effect of bamboo vinegars' compounds on preliminary safety evaluation.

The preliminary safety evaluation, including cytotoxicity and mutagenicity, is performed in accordance with the Ames test [32], a widely used convenient and short-term assay with predictable accuracy for carcinogen up to 72–91% [35]. Referring to the Ames test, as proposed by Ames *et al*. [32], Waleh *et al*. [36], which indicates that if the sample is toxic for the strain, the bacterial count decreases, and the test result is likely to be misjudged. Therefore, the specimen cytotoxicity has to be tested before the mutagenicity test, in order to evaluate whether the growth of the strain is influenced. The mutagenicity can be implemented if there is no toxicity [32, 36]. In this report, the *S. typhimurium* TA98 and TA100 are used as test strains. TA98 is the strain sensitive to frame shifting mutation, as caused by specific mutagens; TA100 is the strain

The methods of the cytotoxicity for the bamboo charcoal and vinegars are taken 1.0, 2.5, 5.0, 7.5, and 10.0 mg of bamboo charcoal, as well as 0.1 mL of bamboo vinegars, collected at different

**2. Ames test for bamboo charcoal and vinegars**

for testing base substitution variation [37].

**2.1. Cytotoxicity**

Bamboo and its products show good prospects for commercial applications, when considering the need for the protection of our wood resources and environmental balance. It is therefore important to study the characteristics of bamboo and its by-products in order to make good use of them. Domestic and foreign manufacturers and researchers have invested a great deal of money, labor and time to discover the characteristics and functions of charcoal in recent years. Bamboo charcoals are mainly derived from 4-year-old or older bamboo as raw materials [4–7]. The utilization of bamboo charcoal, conventionally regarded as fuel, is widely applied to daily life or/and industry. The use of bamboo charcoal is more wide and diverse because it is a porous material with a high specific surface area that has lots of functions, such as indoor deodorization, humidity control, water quality improvement, air purification and so on [5, 8, 9]. Recently, there has been a tendency to maintain good health from food products. Some food producers have added charcoal materials into food products, for example, charcoal bread/ cookies, charcoal peanuts, charcoal ice cream, etc. This is advertised as being able to absorb unclean substances, such as heavy metal elements, and producers have exaggerated that these materials can clean the intestines and stomach after eating. However, in May of 2006, the Department of Health's Executive Yuan, Taiwan, announces that the charcoals can only be used as colorants of food without any medical and health effects, that is, as a natural black pigment only [10]. The charcoals can be added as a pigment in food, but it is a profound question whether or not residue *in vivo* causes any harm by inducing cell lesions or carcinogens.

The application of bamboo vinegar (brown-red transparent liquids), even the compounds that are complex and different, is mainly able to be divided into three main portions: acid, phenol, and neutral compounds [11]. The vinegar consists of 80–200 compounds: 32% organic acid, 40% phenolic compound, 3% aldehyde, 5% alkone compound, 5% alcohol compound, 4% ester compound, and 5% others. When bamboo vinegar is dehydrated, there is usually 80% water [12–15]. The organic compounds in bamboo vinegars may have practical applications even when present in only trace quantities [14, 16], such as in improving soil, promoting crops and preventing worm growth, as well as reducing agricultural chemicals, compost odor and sterilization [12]. Recently, bamboo vinegars have been developed that are beneficial for promoting growth of plants to as a plant root growth promoter or a pH value adjuster of cultural media [17–19]. It is also effective when used against allergies [20], in healthy drinks [13, 21, 22], as a virus/fungi/bacterial resistant [16, 23–27] and as an agent of antioxidation, especially for a resistant lipid oxidation effect [15]. As stated in the above references, the commercial production of bamboo vinegar is being increased and highly valued for its diverse effective uses in Taiwan. However, bamboo vinegars collect at the exit of chimney of earthen or furnace kiln, when the carbonization temperature of bamboo is raised to over 500°C, produce some carcinogenic polycyclic aromatic hydrocarbons (PAHs), such as naphthalene and phenanthrene [28–30]. The concentrations of these toxics increase with the increase in temperature as well. Even though the council of agriculture in Taiwan has submitted certified agricultural standards of forest products (2004) to prove that it is necessary for bamboo vinegars to be collected at 80–150°C at an exit of chimney of earthen kiln and below 350°C for a furnace kiln [31], the collected bamboo vinegars from above this range of temperatures are necessary to evaluate the potential of mutagenic and carcinogenic agents, due to the fact that they are omnipresent in the human environment and seem impossible to completely eliminate.

Ames *et al*. [32] reports that for screening of environmental mutagens and carcinogens, the Ames test (safety evaluation), a convenient method to evaluate mutagenic activities of these chemicals, has been developed, and McCann *et al*. and Sugimura *et al*. have suggested that the mutagenic activities of a number of chemicals correlate well with the carcinogenic activities [33, 34]. The main goal of this chapter is to realize fundamental knowledge of the bamboo charcoal/vinegars as functional additives, while at the same time understanding the preliminary safety evaluation of both using the bacterial mutation assay on *Salmonella typhimurium* (*S. typhimurium*) TA98 and TA100 strains with and without an extrinsic metabolic activation system. Moreover, because the reverse mutation assay (antimutagenic activity) has an array of prospective applications in human care, such as the increasing application in drinks and food antioxidation, and has not been reported for the antimutagenic activities of bamboo vinegars that have been made so far, the antimutagenic activity of the vinegars is reported. Besides, the basic compounds of vinegars, collected at different temperatures from the exit of earthen kiln chimney and analyzed by using gas chromatography-mass spectroscopy, are considered, in order to realized the effect of bamboo vinegars' compounds on preliminary safety evaluation.
