Addition Of Lemon Research Articles

Phytochemical Phytochemical Compounds and Antihyperglycemic Activities from Beverage Composed Pluchea indica Less-Black Tea-Honey

Pluchea indica Less has been developed into tea bag because it contains a number of phytochemical compounds, such as lignin, terpenes, benzoids, phenylpropanoids, alkanes, saponins, catechins, alkaloids, tannins, sterols, phenolhydroquinones, and flavonoids, which have been shown to have several biological activities, such as antioxidants, anti-inflammatory, anticholesterol, and antihyperglycemic. In its development, pluchea tea can be combined with black tea to produce certain functional values. Consumption of pluchea-black tea in daily life can be done with the addition of lemon or honey to increase antihyperglycemic activity. However, this study focused on determining the profile of phytochemical compounds and antihyperglycemic activity of pluchea-black tea honey drink. The research design used was a Randomized Block Design (RAK) with one factor including honey concentration consisting of six treatment levels: 0, 1, 2, 3, 4 and 5% (v/v). Each treatment was repeated four times. Parameters carried out are the profile of phytochemical compounds and antihyperglycemic activity through in vitro analysis, namely the activity of inhibiting a-amylase and a-glucosidase enzymes. The results showed that the use of honey in the manufacture of pluchea-black tea had an effect on the profile of phytochemical compounds and antihyperglycemic activity. The use of honey with a concentration of 5% produced the highest antihyperglycemic activity, 73.21±3.57% for the ability to inhibit the alpha-amylase enzyme and 77.27±5.25% for the ability to inhibit the alpha-glucosidase enzyme, respectively

Physicochemical and sensory characteristics of cascara syrup with the addition of lemon (Citrus limon) extract

Cascara is a drink made from dried coffee cherry skin that has the potential aspects to be further developed into syrup. The processing of cascara syrup with the addition of lemon (Citrus limon) is expected to produce a preferred syrup. This study aims to determine the physicochemical and sensory characteristics of cascara syrup with the addition of lemon extract. This study used a factorial Completely Randomized Design (CRD) with 2 factors, the concentration of cascara extract (C1 = 20% and C2 = 25%) and lemon extract (L1 = 0%, L2 = 3% and L3 = 5%). The parameter analyzed were pH, total soluble solid (TSS), total fenol, vitamin C and hedonic taste. The results showed that the addition of lemon affects the physicochemical and sensory characteristics of the cascara syrup produced. The higher cascara extract added, the total soluble solid of cascara syrup produced will be increased. The more lemons added, vitamin C content and the hedonic taste also increase, but pH value decreased. The best treatment was obtained from cascara syrup with 25% cascara extract and 5% lemon extract (C2L3) with a pH value of 3.91; total soluble solid 4.89 °Brix; vitamin C 10.83 mg/100g; total phenol 31.62 mg/ml and hedonic taste 3.72 (like).

Organoleptic evaluation and chemical tests of various formulations of kencur drink (Kaemfelia galanga L.): efforts to find the best formulation to increase body immunity

Kencur drink is one of the traditional drinks that has been known to be popular and has become an icon for daily healthy drinks. Kencur drink is very useful in preventing and treating diarrhea in Indonesia, can prevent colds and flu. Kencur can also prevent cancer, stop vomiting, prevent and treat fungi, lower cholesterol and improve appetite. Therefore, various ways are done so that this kencur drink remains a healthy daily drink, such as giving a mixture of other ingredients, one of which is the provision of stevia leaf extract. There is also the addition of lemon, brown sugar, and others. Methods in the study with the addition of stevia extract were increased from groups one to six. While other compositions remain such as kencur, lemon and brown sugar. From the results of the study it was obtained that the addition of stevia leaf extract was the highest most preferred and contained vitamin C which was more abundant with other groups. It was concluded that giving stevia leaf extract as much as 24.24% became a favorite drink and had the highest vitamin C content

Physicochemical properties, consumer acceptability and microbial quality of saccharified sweet potato juice preserved with lemon

In this study, saccharified sweet potato juice preserved with lemon juice at different concentrations of 0.5, 1.0, 1.5, 2.0, 2.5 and 3.0%, was formulated. Physicochemical, sensory, and microbial quality of the juice stored for 48 hr were analyzed. The pH and brix values decreased, but the total titratable acidity increased as a result of added lemon juice. There was a significant amount of Vitamin-C, B6, and B9 in the samples, while the antinutritional component (phytate, saponin and tannin) of the juice was generally low compared with the generally acceptable limit. The sensory results showed that the sample with 2.5% lemon juice was the most accepted. The rate of microbial growth within a 48 hr storage period decreased with the addition of lemon and there was no record of fecal coliform bacteria growth. Lemon can be used as a source of natural preservatives and a substitute for artificial preservatives for sweet potato juice.

Impact of heat treatment and flavorings on the antioxidant capacity of black and green tea

AbstractThe high antioxidant capacity of tea is well-known, but the effect of flavorings like honey or lemon has been less studied. Their antioxidants can interact with each other, the global result being also affected by the brewing temperature.The combined effect of heat (55 and 80 °C) and flavorings (acacia and honeydew honeys, lemon juice) on the total polyphenol, total flavonoid content and antioxidant capacity of black and green teas was studied.In many cases higher antioxidant capacity was obtained at 80 °C. Teas flavored with honeydew honey had higher antioxidant capacity than those containing acacia honey. Addition of lemon decreased the antioxidant capacity of tea with honey. No synergies were confirmed in any of the compositions investigated. Vitamin C content of lemon-containing black tea was reduced by half at 80 °C compared to tea brewed at 55 °C; while honey was shown to partly prevent this loss of ascorbic acid.

Toward developing natural histologic stains using anthocyanins: A novel approach.

Introduction:In the present-day scenario, wherein histotechnological laboratory personnel come into contact with numerous hazardous chemicals every day, laboratories are emphasizing on development of safer and environment-friendly alternatives globally which are easily available and feasible. In this context, we have attempted to utilize anthocyanins, a family of pigments naturally occurring in fruits and flowers and which are already used as natural food colorants, for assessing their utility as histological stains.Materials and methods:Juices of thin consistency from well-ripened pomegranates were obtained by using a juicer with blender functions. Formalin-fixed paraffin-embedded 4 μm thin sections were immersed in this solution for 2 h, during which the solution was periodically monitored. Several modifications were attempted such as the addition of Citrus limon (lemon) extract or acetic acid, change in orientation of the slides and refrigeration of the solution during the staining procedure.Results:A peculiar pattern of reasonably diagnostic staining was observed in which the basal and suprabasal cells, basement membrane, inflammatory cells and collagen fibers stained prominently with a magenta color. The addition of lemon, horizontal orientation of slides and refrigeration each separately led to an improvement in staining characteristics. The addition of 4% acetic acid and refrigeration of the solution each led to an improvement in longevity of the staining solution.Conclusion:Anthocyanins could potentially be used as viable histological stains having advantages of availability, feasibility, color stability and nontoxicity, although numerous modifications to improve longevity of staining solution and staining characteristics are warranted by further research for which the present study could serve as a pretext.

Produksi Enzim Pektinase dari Limbah Kulit Pisang oleh Kapang Aspergillus niger dan Aplikasinya Terhadap Klarifikasi Minuman Fungsional Jahe Lemon

Pectinase enzymes are commercial enzymes that can damage pectin by breaking down polygalacturonate acid into monogalacturonate acid through the release of glycosidic bonds. Pectinase enzymes can be produced from a variety of microorganisms, especially from types of mold such as Aspergillus niger using waste as a substrate like a banana peel. Lemon ginger drink is a functional beverage innovation made from ginger with the addition of lemon to add a refreshing sensation. However, the cloudy, pale, and sedimentary appearance in lemon ginger drink causes a lack of interest in consumers, especially young people. When consuming functional drinks such as lemon ginger, there is turbidity caused by polysaccharides such as pectin. Therefore, enzymatic clarification using pectinase is an effective way to reduce pectin in this drink. This study aims to find out the concentration of Aspergillus niger in producing pectinase enzymes from banana peel waste and its application to the clarification of lemon ginger drinks. The method used in this study was a randomized design group (RAK) consisting of 1 factor, the treatment of concentrations of Aspergillus niger 0 mL, 1 mL, 2 mL, 4 mL, and 6 mL. Then followed by the application of pectinase enzymes produced in the clarification of lemon ginger drink, concentration of 0%; 0,08%; 0,10%; 0,12%; 0,16%; 0,20%; and 0.24%. The Data obtained is analyzed using a printing analysis (ANOVA), and if there is influence, then proceed using BNJ test at a real level of 5%. The results showed that the concentration of Aspergillus niger suspension is best in producing pectinase enzymes of 6 mL, with the enzyme activity of 1.83 U/ml. Then the application of pectinase enzyme in the clarification of lemon ginger drink with a concentration of 0.16% better in improving lower clarity and viscosity of the resulting lemon ginger drink.

Addition of lemon before boiling chlorinated tap water: A strategy to control halogenated disinfection byproducts

Chlorine disinfection is required to inactivate pathogens in drinking water, but it inevitably generates potentially toxic halogenated disinfection byproducts (halo-DBPs). A previous study has reported that the addition of ascorbate to tap water before boiling could significantly decrease the concentration of overall halo-DBPs in the boiled water. Since the fruit lemon is rich in vitamin C (i.e., ascorbic acid), adding it to tap water followed by heating and boiling in an effort to decrease levels of halo-DBPs was investigated in this study. We examined three approaches that produce lemon water: (i) adding lemon to tap water at room temperature, termed “Lemon”; (ii) adding lemon to boiled tap water (at 100 °C) and then cooling to room temperature, termed “Boiling + Lemon”; and (iii) adding lemon to tap water then boiling and cooling to room temperature, termed “Lemon + Boiling”. The concentrations of total and individual halo-DBPs in the resultant water samples were quantified with high-performance liquid chromatography-tandem mass spectrometry and the cytotoxicity of DBP mixtures extracted from the water samples was evaluated using human epithelial colorectal adenocarcinoma Caco-2 cells and hepatoma HepG2 cells. Our results show that the “Lemon + Boiling” approach substantially decreased the concentrations of halo-DBPs and the cytotoxicity of tap water. This strategy could be applied to control halo-DBPs, as well as to lower the adverse health effects of halo-DBPs on humans through tap water ingestion.

Possible side effects of sugar supplementary nutrition on honey bee health

Food shortage, along with biotic stressors, contributes to winter honey bee colony losses. In autumn, to support honey bee colonies and prepare them for the winter season, beekeepers can supply homemade syrups which could contain compounds with possible negative side effects. In this study, we investigated the toxicity of one of those compounds (e.g., hydroxymethylfurfural, HMF) at doses consistent with literature data both to healthy bees and bees challenged with their most important parasite (i.e., Varroa destructor). To strengthen available data on HMF concentration in sugar syrups, we also investigated HMF formation in homemade 2:1 inverted sugar syrup, considering, in particular, the influence of temperature or boiling time on different homemade sugar syrups according to their acidity. Finally, we studied the effects of the acidity of sugar syrups on honeybee survival, and tested whether or not sucrose inversion through acidification is really necessary. We show that doses of HMF similar to those reported as sublethal in the literature appear to be non-toxic even to mite infested bees. However, the amount of HMF that can be found in homemade syrups, which increases with temperature and acidity, can be much higher and can cause significant bee mortality. Moreover, we highlighted the detrimental effect of syrups acidity on honeybee survival, suggesting that the addition of lemon or any other acidifying substance to invert the sucrose could be harmful and not necessary. Our results suggest a responsible approach to homemade colony nutrition.

Efficacy of the dehydrated lemon peels on the immunity, enzymatic antioxidant capacity and growth of Nile tilapia (Oreochromis niloticus) and African catfish (Clarias gariepinus)

This work was performed to investigate the effect of the dietary addition of lemon, Citrus limon (L.) Burm. peels on the growth performance, antioxidant activity, immune status, and disease resistance against Aeromonas hydrophila in two common freshwater fish species (Nile tilapia, Oreochromis niloticus and African catfish, Clarias gariepinus). The fishes were randomly distributed at 10 fish per 60 L aquariums, and fed on three different diets (a control basal diet and two supplemented diets with 1% and 2% dried C. limon peels powder) for 45 days. The growth performance was insignificantly decreased in Nile tilapia fed on 2% followed by 1% C. limon peels supplemented diets and in African catfish fed on 2% C. limon peels when compared with the control fishes. Serum glucose was decreased with increasing levels of C. limon peels (2% followed by 1%) in Nile tilapia diets, whereas no significant effects were observed in African catfish. The cortisol levels remained unchanged in both fish species. However, significant elevation (p < .05) in the level of catalase (CAT) enzyme was seen in both fish species fed on C. limon peels (1% and 2%). Superoxide dismutase (SOD) was significantly increased in African catfish fed on C. limon peels (1% and 2%), whereas no significant change was noted in Nile tilapia. The reduced glutathione (GSH) content was significantly increased in both fish species fed on 2% C. limon peels; whereas no significant change was detected when they fed on 1% C. limon peels. The C. limon peels supplemented diets enhanced the serum lysozymes activity, myeloperoxidase (MPO) level and the phagocytic activity in both fish species. Moreover, nitric oxide level was significantly increased in Nile tilapia fed on 1% and 2% C. limon peels, while no significant change was observed in African catfish. The relative percentage survival (RPS), post A. hydrophila challenge, was found to be boosted in both fish species fed on C. limon peels (1% and 2%), when compared with the control fishes. The results elucidated that the inclusion of C. limon peels in Nile tilapia and African catfish diets could improve the enzymatic antioxidant capacity and immune response, but no significant effect on growth performance was observed. Thus, C. limon peels as a by-product could be successfully used as a cheap feed additive in aquaculture to enhance disease resistance.

Effect of Different Saudi Honey Types Mixed with Natural Substances on Some Bacterial Strains

To evaluate the antibacterial eff ects of three types of Saudi honey (Feghra, Sider and Natural honey) alone and mixed with ginger or lemon in comparison to Manuka honey as a potential natural antibacterial agent. Saudi honeys were evaluated against five types of bacterial strains; Klebsiella pneumoniae, Staphylococcus aureus, Pseudomonas aeruginosa, Haemophilus influenzae and Streptococcus pneumoniae. Chocolate agars were prepared first with different concentrations of each type of honey, and then with specific concentrations either of ginger or lemon added to honey. Bacterial species were inoculated on each agar and incubated at 37oC in a CO2 incubator overnight. Significant differences were found between diff erent types of honey and different concentrations of the same honey on bacterial growth. There are no significant differences and synergistic effects when adding ginger to diff erent honey types. Addition of lemon show significant differences and good synergistic effects against all tested bacterial species except Klebsiella pneumoniae and Staphylococcus aureus at 15 and 20% honey concentration. In conclusion, antibacterial effects of different types of honey are type and concentration dependent. Adding lemon to the different types of honey changes the pH and acidity and increases the honey’s antibacterial effect.

Incorporation of citrus essential oils into bacterial cellulose-based edible films and assessment of their physical properties

The use of edible films in food protection and preservation has recently gained more interest since they offer several advantages over synthetic packaging materials. Biocellulose (BC) offers great opportunity as edible film due to their unique physical and mechanical properties. In this study, biocellulose films were prepared by solution casting with addition of 30% carboxymethyl cellulose (CMC) and 30% glycerol as the homogenizer and plasticizer, respectively. Furthermore, various citrus essential oils (EOs) including lemon, lime, and sweet orange were added at 50% w/w of BC dried weight. The solutions were then cast on the tray and allowed to dry in the air convection oven at 40°C overnight. The films were characterized for water solubility, tensile strength (TS), elongation at break (EB), water vapour transmission rate (WVTR), and color. Those characteristics may influence consumer acceptability of the packaged products. Results revealed that addition of lemon and sweet orange EOs into BC-based edible film decreased water solubility and TS, but improved EB, as these oils acted as plasticizers in the film. However, different trend was observed for BC-based film incorporated with lime oil, which had higher solubility and TS, but lower EB and WVTR compared with that of control film. Addition of citrus EOs into BC-based films did not have much effect on color properties as stated in L*, a*, and b* values.

Characterisation of lemon-flavoured olive oils

Fresh lemons (Citrus limon L.) from two locations in Italy were added to fresh olives before milling them to produce flavoured olive oils (FOO). FOOs were characterized for their quality parameters, fatty acid composition, biophenol content, volatile compound composition and sensory profile. Sensory results showed that lemon volatiles would mask negative notes of olive oil obtained from olives with slight off-flavours by adding strong notes of lemon leaf, albedo and lemon juice, while they decreased the positive notes of olive fruit, green, leaf and bitter-pungent from good quality olives. Flavouring OO with lemon significantly affected quality indices, with a significant increase of the acidity value and UV indices. OO flavouring with fresh lemon also affected the phenolic compounds, particularly the simplest forms, hydroxytyrosol and tyrosol. A dramatic decrease of the concentration of aldehydic and dialdehydic forms of oleuropein was also observed in FOO. As expected, volatile profile of virgin OO dramatically changed due to lemons addition, which caused the presence of several terpene compounds, namely limonene, α-pinene, β-pinene, sabinene, β-mircene and γ-terpinene. In contrast, virgin OO volatile compounds decreased with lemon addition. In conclusion, addition of lemon to OO should be carried out by considering these results, as well as the legislation for this kind of product.

Classification of different types of beer according to their colour characteristics

Twenty-two samples from different beers have been investigated in two colour systems - XYZ and SIELab - and have been characterised according to their colour parameters. The goals of the current study were to conduct correlation and discriminant analysis and to find the inner relation between the studied indices. K-means cluster has been used to compare and group the tested types of beer based on their similarity. To apply the K-Cluster analysis it is required that the number of clusters be determined in advance. The variant K = 4 was worked out. The first cluster unified all bright beers, the second one contained samples with fruits, the third one contained samples with addition of lemon, the fourth unified the samples of dark beers. By applying the discriminant analysis it is possible to help selections in the establishment of the type of beer. The proposed model correctly describes the types of beer on the Bulgarian market and it can be used for determining the affiliation of the beer which is not used in obtained model. One sample has been chosen from each cluster and the digital image has been obtained. It confirms the color parameters in the color system XYZ and SIELab. These facts can be used for elaboration for express estimation of beer by color.

Determination of lemon and carbonate effects on caffeine content of various teas and investigation of daily caffeine intakes / Çeşitli çayların içerdikleri kafein miktarlarına limon ve karbonatın etkisi ve günlük alım miktarlarının incelenmesi

Abstract Objective: Tea (Camellia sinensis), has been used for health field in thousands of years. Caffeine is one of the key component in tea and investigation of caffeine is a popular working subject among the researches. The novelty of this study is not only the determination of the caffeine contents of the teas, but also how addition of lemon and carbonate effects the caffeine contents. Another aim of the study is the investigation of the daily caffeine intakes from teas. Methods: Tea infusions were prepared and caffeine contents were extracted by using chloroform and determined by UV-Vis Spectrophotometer. For lemon and carbonate addition experiments, lemon was added before the caffeine analysis and carbonate was added at the beginning. Results: Maximum caffeine contents from highest to lowest were seen in black, earl grey and green in classic teas; fennel, mint and sage in herbal teas; lemon, apple and rosehip in fruit teas. With lemon addition caffeine contents were increased except green tea and with carbonate addition caffeine contents were decreased except black and fennel tea. Daily caffeine intakes are found between 32.10% (green tea with carbonate) - 77.20% (black tea with lemon), 1.85% (sage tea with carbonate) - 4.05% (fennel tea with lemon) and 2.10% (rosehip with carbonate) - 4.00% (lemon tea with lemon) in classic, herbal and fruit teas, respectively. Conclusion: The significance of this study indicates that herbal and fruit teas contain caffeine, which is assumed zero in literature. The caffeine amount of herbal teas (20.79±0.36-30.68±0.63 ppm) were found barely higher than the fruit teas (22.87±0.54-28.54±0.75 ppm) but daily maximum caffeine intakes were found less than 5%. The daily maximum caffeine intakes were found in the teas as 525.36±2.84-20.79±0.36 ppm, where lemon addition increased to 617.90±3.54-22.97±0.58 ppm and carbonate addition decreased to 488.54±2.05-16.84±0.28 ppm.

Optimization of Shelf Stability of Sugarcane Juice with Natural Preservatives

Extracts of moringa seed and leaf (Moringa oleifera); lemon (Citrus limon) and ginger (Zingiber officinale) were added to fresh sugarcane juice in different combinations and evaluated on storage at 2, 4 and 30C. Combination of moringa seed extract with lemon and ginger showed high antimicrobial activity when compared with sodium benzoate (as chemical preservative), at the permitted level. Lemon lowered the pH of sugarcane juice to 3.01 and inhibited the growth of microorganisms during storage. Further, phytochemical analysis of methanol extract of moringa seeds and leaves revealed polyphenols, flavonoids, tannins and terpenoid compounds. It was revealed that good quality sugarcane juice (100 mL) with satisfactory storage stability at refrigeration could be prepared from heat-treated juice (72C for 15 sec) before addition of lemon (3 mL) as a combination of flavor, color enhancer and source of citric acid (antioxidant); moringa (10 mL); ginger (0.6 mL) as flavor enhancer. Practical Applications Sugarcane juice is popularly consumed in India. But large-scale production by mechanizing the manufacturing process is not carried out. Preserving raw sugarcane juice is a challenging problem because it spoils within hours of extraction. The manufacturers rely on the chemical preservatives for extending the shelf-life of sugarcane juice, which restricts its production. The research work was carried out to remove the chemical-dependent constraint with an aim to optimize the shelf-life conditions of sugarcane juice with natural preservatives. A combination of natural preservatives and low temperature storage was found as an effective way of preservation for more than a month with satisfactory sensory qualities. The findings will pave way for the marketability of sugarcane juice.

Effect of pulsed electric field (PEF) treatment on sugarcane juice.

This study was carried out to evaluate the effect of PEF process using static treatment chamber on fresh sugarcane juice with and without addition of lemon and ginger with respect to microbial content, chemical properties, nutrient content and shelf life extention of the product. The fresh sugar cane juice without addition of lemon and ginger treated at different field strengths (30kVcm-1 and 50kVcm-1) and different pulse numbers (150, 300) was initially investigated by storage at room temperature (31°C) and refrigeration temperature (4°C) for 30days. The PEF effect on fresh sugar cane juice at room temperature and refrigerated temperature was compared with untreated sample (31°C). At the end of the storage period samples treated at field strength 30kVcm-1, 150 pulses were found to be stable compared with untreated sample. The second experimental study of PEF process was done on fresh sugarcane juice with the addition of lemon and ginger for fourteen days at different electric field intensities (10kVcm-1, 20kVcm-1 and 30kVcm-1) with the same pulse number (150 pulses) and stored 4°C. Even better reduction of microbes was achieved with PEF treatment condition of field strength 20kVcm-1, 150 pulses in the presence of lemon and ginger. The sensory attributes of untreated fresh sugarcane juice were maintained up to only two days, but for the PEF treated sample, shelf life was extened up to seven days. Further, addition of lemon and ginger in the PEF treated sugarcane juice doubled the shelf life up to fourteen days.

Shelf stable ready to serve sugarcane juice technology: development and economic analysis

The variety Coj 85 was selected for preparing sugarcane juice beverage on the basis of yield and sensory attributes from two promising varieties of sugarcane. Sugarcane juice beverage samples were prepared by pasteurizing the sugarcane juice at 70°C for 10 minutes and adding flavourings and salt. The result revealed that good quality beverage from sugarcane juice of variety COJ 85 can be prepared by addition of lemon as flavor enhancer and source of citric acid (anti oxidant), salt as flavoring compound and mint and ginger as flavor enhancer. Sugarcane juice is a very popular drink in India but still it is rarely available commercially in packaged form, since it is traditionally sold in Punjab by roadside vendors, often in unhygienic conditions. The technologies should be developed for ready to serve sugarcane and making it a popular health drink.

DETERMINATION OF THE EFFECT OF LEMON ADDITION UPON ELEMENT CONCENTRATIONS IN TEA

Consumption of tea is a popular tradition in Turkey. In this article, non essential and toxic element concentrations were determined in infusions and lemon added infusions in widely consumed Turkish teas (black, earl grey, and green tea). Element concentrations were found to be in the order of aluminum > nickel > barium in black and earl grey teas. In green tea, the order was changed to aluminum > nickel > lead > barium. The concentrations of arsenic and antimony were below the detection limit of the inductively coupled plasma optical emission spectrometry method employed. The addition of lemon increased aluminum, cadmium, and lead concentrations in all teas whereas nickel concentration increased in black and green tea but decreased in earl grey. The barium concentration was same at all tea samples. In comparison with the recommended daily allowance ratios, the amount of aluminum consumed is between 13.167–24.396% in males and 17.556–32.528% in females for people who consume 200 mL of teas daily. Other elements (cadmium, lead, nickel, barium) which are a concern for tea consumption were determined and the hazard index of daily tea drinking was found to be in the safe range except for green tea with lemon addition.

Nutrients and antinutrients composition of raw, cooked and sun-dried sweet potato leaves

Traditional indigenous vegetables are the most economically efficient source of micronutrients in terms of both land required and production costs per unit. Promotion of production and consumption of such micronutrient-rich foods will improve intakes, the overall diet, and health status. This study aimed to determine nutrient (iron, calcium, vitamin A and ascorbic acid) and anti-nutrient (oxalates and polyphenols) contents in raw, cooked and dried sweet potato leaves Two varieties of sweet potatoes, which were identified as commonly grown for leaves consumption were analyzed at Department of Food Technology, Sokoine University of Agriculture and at the Government Chief Chemist Laboratory Tanzania. The analysis included proximate, nutrient (ascorbic acid, carotenoids, iron and calcium) and anti-nutrient (oxalate and polyphenols) composition. The purple midrib sweet potato leaves were further analyzed for nutrient and anti-nutrient retention after cooking (with and without lemon) and open sun-drying (with and without salting). There was no significant difference (P>0.05) between the two varieties in crude protein, crude lipid and moisture content. The purple midrib sweet potato leaves had significantly (P<0.05) higher ash, crude fibre, carotenoids, calcium and iron contents while the green midrib sweet potato leaves had significantly (P<0.05) higher ascorbic acid content. The polyphenols were about 4 times higher in the purple midrib sweet potato leaves (22.16%) as compared to that of the green ones (5.28%), which had significantly higher oxalate levels (3730 mg/100g). Drying with salt and cooking with lemon reduced polyphenols significantly (p<0.05), with retention of 42% and 56% respectively; while cooking with lemon lowered significantly the oxalate levels. The traditional methods of cooking SPL with addition of lemon is advantageous because it reduces polyphenols while retaining higher levels of minerals, β carotene and vitamin C. Drying with salt results in a nutritionally and organoleptically good product, hence, drying with salt and cooking with addition of lemon is encouraged. Since the sweet potato leaves are harvested more than once before the plant is uprooted, further studies are recommended to assess whether there is variation in nutrient and anti-nutrient contents in consecutive harvests. Key words: Sweet potato leaves, nutrients, antinutrients