"The First Edible Acidulant"---Citric Acid

Citric Acid Introduction

Citric acid (C6H8O7) is an important organic acid with multiple functions. It is a white crystalline powder at room temperature, almost odorless, widely found in citrus fruits, and is one of the intermediate products of the tricarboxylic acid cycle in the process of cellular energy metabolism. Citric acid not only plays a key role in nature, but also has important applications in the food processing industry, and is often called the "first edible acidifier". Its unique sour taste makes it a common ingredient in many foods. It can not only provide a refreshing sour taste, but also has multiple functions such as solubilization, buffering, and flavor enhancement.

As an intermediary of energy metabolism in the body, citric acid participates in a variety of physiological processes, including energy conversion, structural maintenance, and enzymatic reactions. It is not only one of the key factors in energy production in the human body, but also one of the most effective organic acids, widely used in supplementing nutrition and promoting health.

In addition, citric acid also has health-care effects, which can promote gastrointestinal motility, help regulate the pH value of the gastrointestinal tract, create an environment conducive to the growth of probiotics, and thus maintain the normal balance of intestinal microorganisms. These effects help improve digestive function, enhance immunity, and enhance the body's ability to resist stress. Therefore, citric acid is not only an important ingredient in the food and pharmaceutical industries, but also plays an important role in maintaining human health.

Physiological Functions and Health Benefits of Citric Acid

1. Improve Intestinal Health

Citric acid can stimulate the small intestinal wall, reflexively slow down the gastric emptying rate, prolong the time that food stays in the stomach, and promote the full mixing of gastric juice and food, thereby improving the digestibility of food. This effect not only helps to improve nutrient absorption, but also reduces the risk of blood sugar rise. Citric acid dissociates in the intestine to release hydrogen ions (H+), lower the pH value, inhibit the growth of pathogenic bacteria, and provide a better growth environment for beneficial bacteria such as lactic acid bacteria, thereby maintaining the balance of intestinal microecology.

2. Promote Digestion and Absorption of Nutrients

Citric acid further improves the efficiency of food digestion and absorption by promoting the secretion of digestive enzymes and enhancing the contraction strength and frequency of digestive tract smooth muscles. It can directly stimulate taste bud cells, promote saliva secretion, and enhance appetite, thereby helping to improve digestive function. The acidic properties of citric acid can also increase the acidity in the stomach, activate pepsin, and further promote the gastrointestinal digestion process.

3. Treat Osteoporosis

The importance of citric acid in bone metabolism is gradually recognized. Studies have shown that citric acid helps promote the proliferation and angiogenesis of vascular endothelial cells, and may regulate bone metabolism through specific signaling pathways (such as the rapamycin target protein signaling pathway). Citric acid can promote the differentiation of osteoblasts, increase the activity of alkaline phosphatase, promote the formation of calcium nodules, and ultimately help restore bone mass.

4. Enhance Immune Function

A moderate amount of citric acid can improve the body's immune function, which may be achieved by promoting the absorption of trace elements, accelerating ATP production, and enhancing the function of immune organs. Studies have shown that citric acid helps increase the content of Cab receptors on red blood cells and promotes the enhancement of immune response.

Market Application and Regulations of Citric Acid

Citric acid has been widely used in food, beverages, daily chemicals, and medicine. In the food processing industry, citric acid, as an acidity regulator, can provide a refreshing sour taste for a variety of foods, and play a role in improving the taste of food and extending the shelf life. In addition, the acid-reducing properties of citric acid also make it used in some health products, especially in promoting digestion and preventing urinary stones.

According to the national standard (GB 1886.235-2016), the physical and chemical indicators of citric acid are strictly required, such as its sulfated ash, sulfate and chloride content must meet the specified standards. These standards ensure the safety and quality of citric acid in food.

Production Technology of Citric Acid

There are three main methods for the production of citric acid: fruit extraction, chemical synthesis and microbial fermentation. Due to the high cost of fruit extraction and chemical synthesis, microbial fermentation has become the mainstream technology for industrial production of citric acid. Using microorganisms such as Aspergillus niger for deep liquid fermentation can not only efficiently produce citric acid under low temperature, low pH and high sugar conditions, but also optimize the yield of citric acid by controlling the fermentation environment. By optimizing the selection of microbial strains, the production efficiency and economic benefits of citric acid have been greatly improved.

In general, citric acid, as a multifunctional organic acid, not only has important applications in the food industry, but also shows great potential in improving intestinal health, promoting digestion and absorption, and treating osteoporosis. With the continuous improvement of production technology, the application scope and market demand of citric acid will continue to expand.