Amino acid, fatty acid, and mineral compositions of fruit, stem, leaf and root of Rubus amabilis from the Qinghai-Tibetan Plateau

Highlights

• Nutrient composition of R. amabilis from Qinghai-Tibetan Plateau studied for 1st time.

• Amino acid, fatty acid, mineral contents of Rubus amabilis were analyzed.

• Results showed that leaves contain higher TAA than other plant parts.

• High amounts of methionine are present in free and total amino acids.

• The leaf contains 36.5% unsaturated fatty acids and linolenic acid.

Abstract

The amino acid, fatty acid, and mineral content of Rubus amabilis harvested from the Qinghai-Tibetan Plateau were analyzed. Results revealed that the total amino acids in the leaves, fruits, roots, and stems of R. amabilis were 17.1, 7.5, 6.5, and 5.7 g, respectively. Further analysis of the amino acids showed that the protein contained nutritionally useful quantities of essential amino acids. The total essential amino acids in the leaves of R. amabilis were 9.3 g ETAAs/100 g. Total fatty acids varied in different parts of R. amabilis. Stearic acid, linolenic acid, linoleic acid, and palmitic acid in the leaf samples were 41.4%, 13.7%, 11.9%, and 6.7%, respectively. Lauric acid, oleic acid, docosahexoenoic acid, and eicosenoic acid were present only in small quantities. Potassium, magnesium, and calcium were the most abundant minerals in the leaf samples. Among the essential trace mineral elements, Fe exhibited the highest content in different parts of R. amabilis.

Introduction

Daily intake of fruit, vegetables, and fatty acids may reduce by approximately 20% to 30% the risk of cardiovascular disease and extend the lifespan of a 40-year-old individual by approximately one year (Peter et al., 2010). In many parts of the Qinghai-Tibetan Plateau (also known as the Himalayan Plateau in the Tibet Autonomous Region and Qinghai Province in western China), fruits and tea plants are seldom grown; thus, individuals rely mainly on wild plants to supplement their diet because of the long-term shortage of fruits. As a result, individuals who consume animal meat and animal-derived products as staple food in the western plateau rely on wild plants such as Rubus amabilis to satisfy their nutritional requirements.

R. amabilis belongs to the Rosaceae family and Rosoideae subfamily. Rosaceae comprises approximately 500 species distributed worldwide (Meng and Finn, 2002, Liu and Wang, 2006, Brown, 2002). R. amabilis is a deciduous shrub widely spread in China (Kunming Institute of Botany, 2003). In the Qinghai-Tibetan Plateau, R. amabilis is highly appreciated and consumed particularly by local populations. R. amabilis fruits are characterized by a distinct and pleasant smell. As source of food and medicine, R. amabilis fruits are eaten fresh or canned by local individuals when in season. The leaves of the plant are also dried and consumed as tea. Roots, stems, and leaves exhibit antiphlogistic, analgesic, antidotal, and antitumor effects (Liu and Wang, 2006). In previous studies, compounds from the genus Rubus and their pharmaceutical functions have been described (Cen et al., 2001, Du, 2007).

Many Rubus species bear fruits. In most countries, fruits derived from Rubus species are commonly used in food and beverage industries to produce wine, beer, soft drinks, preserved and canned foods, and desserts. Dried leaves from Rubus species can be used to prepare tea and herbal tea blends (Brown, 2002). Rubus extract can be applied in traditional medicine as an antimicrobial (Rauha et al., 2000, Tan et al., 2002), anticonvulsant, muscle relaxant (Nogueira and Vassilieff, 2000), and radical scavenging (Moyer et al., 2002) agents.

However, a detailed analysis of the nutrient content of this plant is unavailable. This study aimed to determine the amino acid, fatty acid, and nutrient concentrations in the fruits, leaves, and roots of R. amabilis from the Himalayan Plateau in western China.