Determination of Quality Characteristics in Different Green Tea Products Available in Supermarkets of Sri Lanka

Transcription

1 Determination of Quality Characteristics in Different Green Tea Products Available in Supermarkets of Sri Lanka S.A.D.P.S. Jayawardhane, K.M. Mewan, S.K. Jayasinghe, D.G.N.P. Karunajeewa, M. Neranjan, R.A.N.M De Alwis, N.C. Weerakoon, E.N.U. Edirisinghe Biochemistry Division, Plant Pathology Division, Tea Research Institute of Sri Lanka 1 Outline Introduction Objectives Methodology Results & Discussion Conclusion & Recommendations 2 1

2 Introduction 3 Introduction Ceylon Tea Ceylon Tea is globally renowned for its quality Different types of teas are produced in Sri Lanka; But the term; Ceylon Tea is usually associated with high quality Black Tea (BT) Compared to Ceylon BT market, Ceylon Green Tea (GT) is less well known 4 2

3 Introduction Green Tea (GT) Production of GT in metric tons Global GT production (Mt) 1,559,982 1,665,700 1,752,199 Sri Lankan production (Mt) 3,725 3,195 2,879 Percentage of Sri Lankan contribution to global GT production % 0.24% 0.19% 0.16% Exportation of GT in metric tons Global GT exportation (Mt) 356, Sri Lankan exportation (Mt) Percentage of Sri Lankan contribution to global GT exportation % Source: International Tea committee; Annual bulletin of statistics (2016) 0.87% 0.85% 0.65% 5 Introduction GT Quality Quality of the product depends on optimized conditions maintained throughout the manufacturing process Sorting & Clearing Pan Firing/ Steaming Rolling & Shaping Drying Catechins Polyphenol Oxidase (Polyphenols) Characteristic green color Oxidized Polyphenols (Theaflavins & Thearabigins) Characteristic Golden black color in BT 6 3

4 Introduction GT Quality ISO recommended parameters Total polyphenol content% Water extract % Total ash, water soluble ash & alkalinity% Acid insoluble ash% Crude fiber% Other important parameters relevant to daily tea intake Total antioxidant activity Total amino acid content Fluoride content Aluminum content ph of the tea brew Moisture content Chemical parameters Total aerobic plate count Yeast and mould count Microbiological parameters Organoleptic parameters Total Coliform content Total Escherischia coli content Particle size & Color Brew Color Color of the infused leaves 7 Objectives 8 4

5 Objectives General Objective: To analyze the quality parameters of Green Tea products available in Sri Lanka, for the determination of their compliance to accepted levels Specific Objectives: Determination of ; Organoleptic quality parameters Chemical quality parameters Microbiological quality parameters 9 Methodology 10 5

6 Methodology Collection of GT samples from Sri Lankan supermarket ( A total of 17 different brands of GT) (Each brand; Two batches with different manufacture dates) Determination of; Organoleptic Parameters Chemical Parameters Microbiological Parameters Analysis of quality parameters in Green Tea products 11 Methodology Organoleptic Parameters Microbiological Parameters Chemical Parameters Particle size, Color, Texture and appearance Color of the tea brew Color of the infused leaves Total Aerobic Plate Count Yeast and Mould Count Total Coliform Content Total E.coli Content (Test methods: Sri Lanka standard 516: part 1: 1991, Sri Lanka standard 516: part 2: 1991 and Lanka standard 516: part 3: 1982) ISO Recommended Chemical Parameters Other important parameters relevant for daily tea intake 12 6

7 Chemical parameters - ISO Recommended Parameter Test Requirements Method Green tea Black tea Water Extract % ISO min. 32 min. Total ash % ISO Water soluble ash % ISO min 45min Alkalinity of water soluble ash % ISO Acid insoluble ash % ISO max. 1.0 max. Crude fiber % ISO max. 16.5max. Total Polyphenol % ISO min. 9 min. 13 Chemical parameters Relevant for tea intake Parameter Antioxidant Activity Total Amino acid content Total Fluoride content Total Aluminum content Test method DPPH Assay Ninhydrin method Fluoride ion selective method Spectrophotometric method 14 7

8 Observations & Results 1. Organoleptic parameters observed 15 Organoleptic parameters Particle size and shape 1. Gun Powder- Shotness & Hardness Taste Fishy taste Olive oil taste Color of the brew Apple Green/ Clearness Appearance of infused leaves Non-fermented dark green color 2. Young Hyson Bigger leaf & green curl leaf 3. Fannings- Even sizing & greeness In terms of Organoleptic Scores given 1-10 ; parameters; Out of 17 samples analyzed; Scores (1-3 )- Low quality Low quality 4 Scores (4-6)- Medium quality Medium quality - 10 Scores (7-10)- High quality High quality

9 Organoleptic parameters-particle size and color Color of the particles: Presence of brown-black particles with lack of greenness 17 Organoleptic parameters- Color of the brew and infused leaves Brew Color; Lack of apple green color/ clearness Formation of brownish black color in brew Local GT products Infused leaves ; Fermented dark black color Japanese GT products 18 9

10 TPP % 07/02/2017 Observations & Results 2. Chemical parameters Chemical parameters ISO recommended Total Polyphenols (TPP)% Water Extract% Soluble matters (Phenolic compounds, alkaloids, amino acids, minor soluble substances etc.) determines the quality of tea (Harbowy et al., 1997) Min 11 % Samples Water Extract % TPP% content The characteristic astringency and bitterness of GT depends on adequate content of flavonoids (Balentine, 1992) TPP% is an indication of the leaf standard. Water Extract % Min 32% Samples

11 Alkalinity of Water Soluble Ash % Total Ash% Acid Insoluble Ash % Water Soluble Ash % 07/02/2017 Chemical parameters ISO recommended Total ash% - Determines the physiological ash; correlates with mineral content of tea leaves Water soluble ash% - The composition of the ash in tea varies with the maturity of the leaves Alkalinity of water soluble ash% - A considerable amount of total potash is lost by brewing; Acid insoluble ash% - Indication of the contamination of any silica matter during manufacturing process Levels of P, K decreases (Sivasubramanium et al., 1972) 21 Chemical parameters ISO recommended Total ash % Samples 70 Max 8 60 Min 45 Min 4 Alkalinity of water soluble ash % Max 3 Min Samples All samples complied with ISO requirement 0 Water soluble ash % Samples Acid insoluble ash % Max 1 Samples

12 Fluoride content g/120 ml Crude Fiber % 07/02/2017 Chemical parameters ISO recommended Max 16.5% Crude fiber % Samples Crude Fiber % An indication of the quality in starting leaf material. Increases the fiber content 23 Chemical parameters Important parameters for tea intake Fluoride content(mg/ 120 ml) in tea brew RDA for adult 4 mg/ day 4Cups 3Cups 2Cups 1Cup RDA for children 2 mg/ day Samples Fluoride content Tea plant accumulates and stores more fluoride & up to 98% of the accumulated fluoride is stored in its leaves (Cao et al., 2006) Total antioxidant activity 11.0 % 11.6 % (Trolox equivalent) Total amino acid content 0.45 % % Dry matter content 88.9 % % 24 12

13 Moisture % 07/02/2017 Chemical parameters Important parameters for tea intake Moisture content High moisture content negatively influence on shelf-life The product moisture content should be controlled between 2.5%-6.5 % for a better quality product ( Adnan et al., 2013) Moisture % % % samples 25 Observations & Results 2. Microbiological parameters 26 13

14 Moisture content % Sample No 07/02/2017 Microbiological Parameters Analyzed; Observed Levels in GT samples Microbiological parameter Total Aerobes per g at 30±1 C Total Yeast & Moulds per g at 25±1 C Total Coliforms per g at 35±1 C Total E. Coli per g Max. Perm. Level 10000(CFU/g) 1000 (CFU/g) 10 (MPN) NIL at 44 ±1 C 9 1 TNTC ND ND 8 4 TNTC ND ND ND ND ND ND ND < <1100 > <1 ND ND <1 ND ND <1 ND ND TNTC ND 27 Microbial contaminations A serious issue???? Locally available GT products : 30 Type of Green Tea (GT) product Locally available GT samples Total Aerobes Total Yeast & Molds Total Coliforms Total E. Coli No of samples exceeded the maximum permissible level

15 Where do microbes come from? Blending????? Transportation Machinery Which Post Past Processing Fresh Packing Factory Tea & Tea of Pan Steaming processing Harvest Handling environment Firing by Plucking made baskets Leaves their step and Operations operations operations??????? crates 29 Future Activities Collection of GT samples from local GT factories, After each of the processing step To identify the mode of the microbial contaminations To get necessary preventive actions for contaminations 30 15

16 Conclusion & Recommendations 31 Conclusion & Recommendations Chemical Parameters Overall Results Total Polyphenol Content(TPP) Water Extract % Total Ash % All achieved the ISO requirement Acid Insoluble Ash % Alkalinity of Water Soluble Ash % Water Soluble Ash % Crude Fiber % Some Concern not on complied quality of with the ISO starting requirement material Antioxidant Activity Varied in a small range Amino Acid Content Fluoride Content Not at a risky level 32 16

17 Conclusion Parameter Overall Results Organoleptic Parameter Appropriate packing materials, packaging Moisture Content Varied greatly conditions from 3%-11% should be used Particle Size Gun Powder, Young Hyson, Fannings Particle Color Light brown, dark brown and greenish brown Optimization of the steaming/ pan firing Infusion Color Black to golden yellow Microbiological Parameters Total Aerobic Plate Count Yeast and Mould count Total Coliforms Total E.coli content Control product moisture content at an acceptable Only a few level samples satisfied with SLS standards Implementation of good manufacturing practices

18 Acknowledgments To all the staff of Biochemistry Division, TRI To Dr. G. Sinniah, former Acting OIC of plant pathology division and all the staff To my dear friend C. Pilapitiya 35 References Adnan, M., Ahmad, A., Ahmed, A., Khalid, N., Hayath, I., Ahmed, I. (2013). Chemical composition and sensory evaluation of tea (Camellia sinensis) commercialized in Pakistan, Pak. J. Bot., 45 (3): Balentine, D. (1992). Manufacturing and chemistry of tea. (In) C.T. Ho, T. Osawa, M. T. Huang, R.T. Rosen (Eds.), Phenolic compounds in food and their effects on health Washington, DC: American Chemical Society. pp Harbowy, M.E., Balentine, D.A., Davies, D.A.P. and Cai, D.Y. (1997). Tea chemistry. Crit. Rev. Plant Sci., 16(5): Malinocuska, E., Inkielewicz, I., Carrnoucuski, W., Szefer, P,J., (2008) Food Chem. Toxicol, 46, 1055 Mohammed, M.I. and Sulaiman, M.A. (2009) Proximate, caffeine and tannin analyses in some brands of tea consumed in Kano Metropolis, Nigeria. Bayero J. Pure Applied Sci., 2: Sri Lanka Tea Board (2011) Ceylon Green Tea, [Online], Available at< 116&Itemid=249&lang=en [Accessed 02/09/2015] 36 18

19 Thank You 37 19