Course:FNH200/Projects/2024/Processing and safety of Turmeric

What is Turmeric?

The history of turmeric begins over four thousand years ago with its earliest recorded use in India. It was originally used as a dye and later recognized for its culinary and medicinal properties. Turmeric is a member of the ginger family, called the Zingiberaceae family. Turmeric reached China by 700 AD and European explorers in the 14th century introduced it to the Western world. Today, turmeric is important to global cuisines, specifically in South Asian, the Middle East and in Southeast Asian dishes. There are different types of turmeric and Cucuma Longa is specifically used in cooking and traditional medicine. Turmeric, or Curcuma Longa, has a history of use in traditional medicinal practices as a herbal medicine for treating liver and digestive disorders. Cultural differences in the usage of turmeric are vast. Indian cooking uses turmeric to give the yellow hue to curry dishes. China uses turmeric in traditional medicine for its anti-inflammatory and pain-relieving effects. Western countries use turmeric as a superfood in smoothies and supplements.

Chemical Analysis

Turmeric Root

Flavour and aroma

Over 100 compounds have been isolated from turmeric, of which the main components of the root are essential oils, including tormerone. The 3 main components responsible for aroma in this plant are arturmerone, turmerone, and zingiberene. 4 polysaccharides including ukonans, β-sitosterole, stigmasterole, and 2-hydroxymethyl anthraquinone are reported in rhizomes. Turmeric extract as a spice has a characteristic pungency, which is mainly due to arturmerone, a component of turmeric oil. Like curcumin, arturmerone has antioxidant, antimicrobial, and anticancer properties. In particular, the flavor of turmeric influences the specific taste of the food to which it is added, and thus the overall sensory appeal of the food, which is an argument against the use of turmeric extract as a food additive.

Nutrients

Turmeric contains approximately 390 kcal in 100 g from 10 g total fat (3 g saturated fat and 0 mg cholesterol), 69.9 g carbohydrates (21 g dietary fiber and 3 g sugars), and 8 g protein. Moreover, it is a good source of omega-3 fatty acids (2.5% α-linolenic acid). Turmeric is a good source of minerals by containing 10 mg sodium, 2500 mg potassium, 0.2 g calcium, 0.26 g phosphorus, and 47.5 mg iron. Finally, it contains 50 mg ascorbic acid, 0.19 mg riboflavin, 0.9 mg thiamine, and 4.8 mg niacin.

How it's Made

Turmeric preparation in India

Turmeric, the rhizomatic spice crop, is grown in the tropics of South East Asia, primarily India, Thailand, and Indonesia among others. The rhizomes grow underground and are gathered for cleaning, boiling, and drying. Open sun drying is the traditional method used to dry the rhizomes but solar tunnel is an efficient new method used in the production process to achieve higher quality results. After the turmeric rhizomes are dried, they are ground into a fine powder with a vibrant orange yellow colour – the powder is what we typically see sold in grocery stores in Canada.

Preservation Methods

Multiple methods of preservation can be used to preserve turmeric powder including thermal processing and irradiation; however, studies indicate that irradiation was a better storage method than thermal processing as it was able to reduce the microbial contamination without damaging the chemical components of turmeric. The study noted that due to the nature of sun drying, spices that use this method are at risk of being contaminated by airborne bacteria or insects.

Storage Method

Turmeric powder should be stored in a cool, dry place away from light to best preserve the powder. The powder is sensitive to light and heat, as it can denature the chemical properties. It is important that it is kept dry to minimize microbial growth. A study on best storage methods of turmeric concluded that a 4 week storage time was ideal, due to the increase in moisture that occurs at week 6.

Safety Regulations

In Canada, the processing of turmeric must abide by all the regulations stated in division 7 of the food and drugs act. These regulations are put in place to ensure a standard of quality and safety for all consumers.

One form of ground turmeric packaging

Turmeric must be whole or ground, dried Curcuma longa L. This is a standard of identity put in place to ensure that there can be no other substances legally labeled as turmeric other than the rhizome Curcuma longa L.

The turmeric product must contain no more than 7 percent total ash, and 1.5 percent of the ash must be insoluble to hydrochloric acid. Ash is created during the processing of turmeric and can contain inorganics that are both desirable and undesirable. Desirable inorganics in ash may include minerals such as calcium, potassium and sodium, but some undesirable inorganics may include soil and sand. Much of the undesirable substances are insoluble to hydrochloric acid; many food industry laboratories run tests on turmeric with hydrochloric acid to determine such contents found in the ash composition. The regulation that turmeric must contain less than 7 percent total ash ensures that no dramatic modifications are made to the turmeric composition, and 1.5 percent of the ash must be insoluble to hydrochloric acid to ensure a low amount of undesirable substances in the ash content.

Turmeric must carry no more than 10 percent moisture. Moisture content relates to the amount of bound or free water contained within the turmeric. Free water can contribute to chemical reactions and microbial growth that may shorten the shelf-life of the turmeric. Although moisture content does not measure the free water contained within the turmeric that may cause spoilage, this regulation is put in place to ensure the stability of turmeric's shelf life regardless of the free water which may be found within the turmeric.

Turmeric must contain at least 3.5 millilitres of volatile oils per 100 grams of spice. Volatile oils are fat-soluble compounds that contribute to the aroma of foods when they interact with receptors in the nasal passage. Aroma constituents in turmeric make massive impacts on the overall flavour of the spice; much of the flavour would be lost without a sufficient amount of volatile oils. Therefore, turmeric must have a minimum of 3.5 millilitres of volatile oils per 100 grams of spice to maintain the potency of the flavour in turmeric.

Nutritional Aspects

Benefits

Curcuma Longa Plant

Curcumin, an extract of turmeric, is a versatile molecule capable of influencing various cellular signalling pathways. It has demonstrated a range of beneficial activities, including anti-inflammatory, hypoglycemic, antioxidant, wound-healing, cognitive, and antimicrobial effects. Given it's powerful properties, numerous studies have been conducted to examine it's potential health benefits, especially in the treatment of heart disease, arthritis, type II diabetes mellitus, alzheimer's disease, metabolic syndrome and multiple gastrointestinal disorders.

Limitations

Poor absorption, rapid metabolism, and increased systemic elimination have been shown to limit turmeric's therapeutic efficacy. However, bioavailability may be increased when curcumin is combined with agents such as piperine, the active component of black pepper, nanoparticles, liposomes, and other complexes. According to a study by Singletary, it was found that the curcuminoids in raw turmeric powder had a significant effect on glucose/insulin regulation and serum lipid profiles in individuals struggling with type II diabetes, metabolic syndrome, prediabetes and hypercholesterolemia.

Daily Intake

In humans, an intake of turmeric powder as high as 8 g/d has apparently been tolerated with only minor adverse consequences, mainly gastrointestinal distress.

Exam Question

Sun drying is a common method used to dry out turmeric rhizomes before being ground into a fine powder. Based on what we have discussed in class, what negative impacts come with using sun drying as a preservation method?

A) Sun drying is weather dependent, making it unreliable in many parts of the world

B) This method is at high risk for infestation by rodents, insects, birds and microorganisms, leading to contamination of the turmeric

C) Sun drying takes a longer time than other preservation methods

D) All of the above (correct answer)

This question assesses students’ comprehensive understanding of the food safety concerns associated with processing and preservation methods and allows them to apply their knowledge in a practical setting. It incorporates concepts discussed in class like contamination, nutrient preservation and foodborne pathogens.