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Durante los últimos años la creciente demanda por parte del consumidor de alimentos frescos, de primera calidad y listos para preparar y servir, ha generado un cambio importante en la aplicación de técnicas de conservación de alimentos, abriéndose nuevas líneas en el mercado. Ante este reto, la industria ha respondido mediante la elaboración de productos minimamente procesados en fresco. Sin embargo, estos alimentos presentan una vida útil corta, principalmente debido a problemas de pardeamiento. La metodología para controlar este tipo de problema se basa en la utilización de antioxidantes y atmósferas modificadas con bajo nivel de O2. Sin embargo, la sola aplicación de estas tecnologías, en muchos casos, resulta poco efectiva para garantizar una vida útil adecuada del producto minimamente procesado. Por lo tanto, resulta necesario seguir estudiando en el desarrollo y aplicación de otras tecnologías que ayuden a mantener la calidad de estos productos durante periodos adecuados para su comercialización. En este proyecto, se pretende estudiar la efectividad de tratamientos antioxidantes con recubrimientos comestibles y el envasado en atmósferas modificadas `no convencionales¿, con el objetivo de reducir el pardeamiento enzimático en productos como alcachofa, berenjena, manzana y caqui minimamente procesados. / Ghidelli, C. (2014). EFFECT OF SOY PROTEIN-BASED EDIBLE COATINGS WITH ANTIOXIDANT ACTIVITY AND MODIFIED ATMOSPHERE PACKAGING ON THE QUALITY OF FRESH-CUT PRODUCES [Tesis doctoral]. Universitat Politècnica de València. https://doi.org/10.4995/Thesis/10251/39104

Crispness is one of the most desirable textural characteristics of breaded fried foods. Consumers often judge the quality of breaded fried foods based on the perceived crispness of the product. Furthermore, today's consumers are showing increasing concern over fat intake. As a result, there is great interest in being able to enhance the crispness and reduce the fat uptake in breaded fried foods without sacrificing other quality attributes. To achieve these goals, modifications to both frying equipment and product formulation have been explored in this study. In this study, two edible film coatings, methylcellulose (MC) and whey protein isolate (WPI) were incorporated into the batter and pre-dust to determine their effect on the crispness of breaded fried chicken nuggets held under a heat lamp for varying time intervals. Crispness was evaluated by both objective (ultrasonic non-destructive evaluation system) and subjective methods. An untrained sensory panel was used to obtain subjective measurements of product crispness. Panelists rated product attributes such as crispness, juiciness, oiliness and flavor on a simple intensity scale. Additionally, panelists rated the liking of the products on a nine-point hedonic scale (1=dislike extremely, 9=like extremely). Two pressure sources (nitrogen gas and steam naturally released from the food material) were used to determine their effects on product crispness, texture, pressed juice, moisture content, fat content and color. Products fried with nitrogen gas as the pressurizing medium produced samples that were comparable to or exceeding the quality of products generated by frying with steam, as it relates to product crispness, texture, pressed juice, moisture content, fat content and color. As related to objective crispness, chicken nuggets fried with nitrogen were significantly crispier (p<0.05) than those fried with steam. Coating type and application also had a significant effect on product crispness. Samples coated with MC in the pre-dust were crispier than samples coated with WPI. However, no significant differences were found in product crispness, juiciness, oiliness or flavor, and overall liking among samples tested by the sensory panel. The results of this study demonstrated that applying an edible film coating to the pre-dust and using nitrogen gas as the pressurizing medium can enhance and maintain the crispness of breaded fried foods. / Master of Science

This research was designed to set up standard procedures for cooking battered fish portions for fast food restaurants and to study the quality of the frying fat under various conditions. Cooking time and temperature are two important factors to determine the quality of battered fish portions. Fat absorption depends on cooking time, surface area of the food, the quality of frying fats and oils and holding times. The amount of fish portions fried in a frying kettle affects the oil temperature. The addition of 0.02% ascorbyl palmitate (AP) unexpectedly reduces color development of the frying oils in simulated studies. It also reduces peroxide and conjugated diene hydroperoxide (CDHP) values and the volatile compounds, such as decanal, 2, 4-decadienal, which indicate that AP has the ability to inhibit thermal oxidation of frying fats/oils. French fries fat has lower CDHP values compared to animal fat-vegetable oils (A-V fat) in simulated studies and fried chicken oil has lower CDHP values compared to vegetable oil partially hydrogenated soybean oil (V-S oil). Peanut oil has higher thermal stability compared to the other frying fats/oils used. According to sensory evaluation, battered fish portions fried in A-V fat with no holding time are the most preferred products, while those fried in V-S oil with no holding time are the least preferred. / M.S.

Food and beverage intake was recorded for five days by 170 males having a mean age of 26 ± 8.1 years and living in·a university community. Differences in nutrient intake and in eating patterns between the subjects were examined in relation to the percentage of kilocalories fat intake contributed to their diet. Division of the subjects into a low, medium, or high ''fat-intake group" was established with 34 subjects consuming ≤33.5 percent fat, 98 subjects consuming >33.5 and ≤42 percent fat, and 38 subjects consuming >42 percent fat of kilocalories. Cluster and factor analyses indicated that the men were not characterized by any one typical pattern of eating. The use of discriminant analysis identified trends in consumption of certain foods consistent with the results from a previous analysis. Between the three groups of subjects there were negligible differences in nutrient intake, except for fat and carbohydrate. Both analyses indicated that the subjects with a high level of dietary fat consumed more of foods rich in fat and slightly more protein, and that the subjects with a diet lower in fat consumed more carbohydrates and alcohol. These results indicate that the majority of the young men would need to make some modifications on types of frequently consumed foods but would not require drastic changes in their diets to reduce their level of fat intake. This data also indicated that intake of other nutrients is not greatly affected by level of fat intake. / M.S.

African leafy vegetables have been shown and suggested to have potential to contribute to human diets and alleviate malnutrition; however, their levels of utilisation are currently low especially in South Africa. This is because there is limited access to these crops due to low availability in the market. Limited access is attributed, in part, to the lack of commercialisation as a result of limited agronomic information describing optimum management options for these leafy vegetables. Availability of such information would contribute to successful commercialisation of these crops. The primary objective of this study was to establish optimum agronomic management factors for Amaranthus cruentus, Corchorus olitorius, Vigna unguiculata and Brassica juncea for irrigated commercial production in South Africa. Seeds of Amaranthus cruentus, Corchorus olitorius were obtained from the Agricultural Research Council seed bank; Vigna unguiculata were obtained from Hydrotech and Brassica juncea seeds were obtained from Stark Ayres. The project consisted of three field studies whose overall objective was to evaluate growth and yield responses of the selected African leafy vegetables to agronomic factors under irrigated commercial production. These field studies comprised of two single factors; summer trials (planting density and nitrogen on three selected crops) and a combined winter trial (nitrogen, irrigation, plant density and planting date on a winter crop). Chapter three (3) investigated the effect of plant density on growth, physiology and yield responses of Amaranthus cruentus, Corchorus olitorius and Vigna unguiculata to three plant densities under drip irrigated commercial production. The plant density levels of 100 000, 66 666 and 50 000 plants/ha were used in the 2011/12 and 2012/13 summer seasons. Parameters measured included chlorophyll content index (CCI), chlorophyll fluorescence (CF), stomatal conductance (SC), leaf number, leaf area index (LAI) and biomass. Amaranthus cruentus and Corchorus olitorius showed better leaf quality at lower plant density of 50 000 plants ha-1 than at 66 666 plants ha-1 and 100 000 plants ha-1. These results are based on bigger leaves expressed as leaf area index (LAI), better colour expressed as chlorophyll (CCI) and higher biomass per plant observed in these crops at 50 000 plants ha-1 in comparison to 66 666 plants ha-1 and 100 000 plants ha-1. In Vigna unguiculata there were no responses observed in LAI and CCI. In Amaranthus cruentus, Corchorus olitorius and Vigna unguiculata fresh and dry mass yield of leaves were higher at 100 000 plants ha-1 compared to other treatments. In A. cruentus and C. olitorius, higher leaf quality parameters (CCI, plant height, leaf number, biomass per plant and LAI) indicated that these crops can perform better at lower densities of 50 000 than at 66 666 plants ha-1 and 100 000 plants ha-1 Therefore, using 50 000 plants ha- 1 is suitable for commercial production of A. cruentus and C. olitorius. In Vigna unguiculata, a plant density of 100 000 plants ha-1 produced the highest fresh and dry mass per unit area without compromising quality in terms of the leaf size (LAI) and colour (CCI). Therefore 100 000 plants ha-1 is a density recommended for commercial production in V. unguiculata.Chapter four (4) was conducted to investigate growth, physiology and yield responses of A. cruentus, C. olitorius and V unguiculata to nitrogen application under drip irrigated commercial production. Three nitrogen treatments levels were used viz. 0, 44 and 88 kg N ha- 1 in 2011/12 season and four nitrogen treatments levels viz. 0, 50, 100 and 125 kg N ha-1 were used in 2012/13 summer season. The nitrogen levels selected for each season were based on recommendations for Amaranthaceae species, Swiss chard (Beta vulgaris L.var cicla) derived from soil analysis of the trial (field) site. Parameters measured included chlorophyll content index (CCI), chlorophyll fluorescence (CF), stomatal conductance (SC), leaf number, leaf area index (LAI) and biomass. Results showed that application of nitrogen at 44 kg N ha- 1 in 2011/12 summer season and 100 kg N ha-1 in 2012/13 summer season improved LAI, CCI, biomass per plants and yield in A. cruentus. A similar trend was observed in C. olitorius except that 44 kg N ha-1 improved stem fresh yield. Further increase in nitrogen fertiliser above 44 kg N ha-1 during the 2011/12 season and above 100 kg N ha-1 in 2012/13 summer season reduced leaf quality and yield in both crops. In V. unguiculata, nitrogen application showed a slight increase in yield values from 0 to 44 kg N ha-1 followed by decrease at 88 kg N ha-1 in 2011/12 summer season; however, this increase in yield was not significant. During the 2012/13 summer season, yield in terms of fresh weight was significantly (P<.001) reduced by applying nitrogen at various levels. However, leaf dry matter content increased significantly (P<.001) with increase in nitrogen from 0 kg up to 100 kg N ha-1, then remained unchanged at 125 kg N ha-1. Therefore, the current study recommends that C. olitorius and A. cruentus could be commercialised at 44 kg N ha-1 and 100 kg N ha-1 which were lower nitrogen application rates than those recommended for Amaranthaceae species. In V. unguiculata, 50 kg N ha-1 improved leaf number; however, this did not translate to any fresh yield advantage, implying that the optimum rate for nitrogen application might be lower than 50 kg N ha-1. Therefore, nitrogen rates less than the ones used in the current study are recommended for V. unguiculata. Chapter five (5) was conducted in winter and it was necessitated by observations made primarily in the previous studies which focused on the effects of single factors such as plant density, planting date and nitrogen deficits. Therefore, there was a need to address interactions between irrigation, nitrogen, spacing and planting date. The objective of this study was to evaluate growth, physiology and yield responses of Brassica juncea to different agronomic and management factors in the 2012 and 2013 seasons. The treatments were as follows: two planting dates in main plot (1 June and 18 July, 2012); two irrigation frequency in sub main plot (once and three times a week); three nitrogen levels (0, 50, 100 kg N ha-1) and three plant densities (133 333, 80 000, 50 000 plants ha-1) as subplots. Parameters measured included chlorophyll content index (CCI), chlorophyll fluorescence (CF), stomatal conductance (SC), leaf number, leaf area index (LAI) and biomass. Results from this study showed a significant interaction effect on plant height, LAI, CCI and CF. Crops irrigated thrice or once a week with 50 kg N ha-1 combined with 50 000 plants ha-1 produced tall plants and bigger leaves (LAI) in the early planting date (1 June) compared to other combinations. Irrigating three times a week combined with nitrogen application at 100 or 50 kg N ha-1 improved CF for late planting date (18 July) in comparison to other combinations. Irrigating once a week combined with nitrogen application at 100 kg N ha-1 increased CCI. There was no significant interaction effect on yield. Application of nitrogen at 50 and 100 kg N ha-1 significantly (P>0.05) increased yield in early and late planting dates compared to the control (0 kg N ha-1), in 2012 and 2013 winter season. Irrigating three times a week led to a significant (P<0.05) increase in yield in the late planting date (18th July) and early planting date (1st June) in 2013 season. Higher plant density of 133 333 plants ha-1 resulted in significantly (P<0.05) higher yield in terms of fresh mass and leaf number in the late planting date 18 July in 2012 and 2013 seasons. However, leaf quality parameters such as leaf size and colour was compromised at 133 333 plants ha-1 relative to 50 000 plants ha-1. Therefore, farmers are recommended to plant early, apply 50 kg N ha-1, irrigate thrice a week and utilise a spacing of 50 000 plants ha-1. The current study indicates that growth and yield of traditional leaf vegetables can be optimised through improved agronomic practise. / Agriculture and Life Sciences / D. Litt. et. Phil. (Agriculture)

Thesis (M.Tech.: Biotechnology)-Dept. of Biotechnology, Durban University of Technology, 2007 xi, 114 leaves / Eighteen traditionally leafy vegetables consumed as food or medicinal compounds by a majority of people in the KwaZulu Natal province of South Africa were analysed for the presence of potentially harmful chemicals (antinutrients) and for their toxicity and mutagenicity. The purpose of the study was to determine whether leafy vegetables were safe for human consumption. Chemical analysis showed that none of the vegetables contained cyanogenic glycosides, however all the vegetables contained oxalic acid ranging from 24.1 mg/ml to 798.2 mg/ml with Solanum nigrum, Portulaca oleracea and Mormodica balsamina showing the highest concentrations. Most of the vegetables contained negligible amounts of phytic acid and saponins, except for Momordica balsamina (3.01 mg/ml and 1.83 mg/ml, respectively). Fourteen of the plants contained alkaloids with Portulaca oleracea having the highest content (1.53 g total alkaloids/5 g leaf material). Eight of the plants were found to inhibit trypsin activity. These chemical analyses were carried out in duplicate and the mean and standard deviation were used. The Ames test revealed that none of the leafy vegetables produced a mutagenic frequency above 1, except 10 000 µg/ml organic extract of Senna occidentalis (mutagenecity considered at mutagenic frequency above 2), thus none were considered mutagenic. All 18 organic extracts did not kill off more than 50% brine shrimp and were thus considered non-toxic. On the other hand the aqueous extracts of seven vegetables, namely, Physalis viscosa, Amaranthus dubius, Justicia flava, Bidens pilosa, Senna occidentalis, Chenopodium album and Ceratotheca triloba, killed more than 50% of the shrimp and are thus considered toxic above 100 µg/ml. The MTT assay carried out on the organic extracts indicated that 17 vegetables did not kill off more than 50% of HepG2 cells and were thus considered non-cytotoxic. The aqueous extracts of four vegetables, namely, Justicia flava, Asystasia gangetica, Momordica balsamin and Senna occidentalis, however killed more than 50% of the shrimp and were thus considered cytotoxic above 1 000 µg/ml. It may be concluded from the antinutrient analyses and the bioassays on the 18 vegetables that caution needs to be maintained with the consumption of certain leafy vegetables included in this study, especially Senna occidentalis.

Submitted by Deyse Queiroz (deysequeirozz@hotmail.com) on 2018-05-29T17:56:21Z No. of bitstreams: 1 INÁCIA DOS SANTOS MOREIRA - DISSERTAÇÃO PPGSA PROFISSIONAL 2014..pdf: 1960619 bytes, checksum: 0eec38ed3470ea1ff2f29f63cf555e2b (MD5) / Made available in DSpace on 2018-05-29T17:56:21Z (GMT). No. of bitstreams: 1 INÁCIA DOS SANTOS MOREIRA - DISSERTAÇÃO PPGSA PROFISSIONAL 2014..pdf: 1960619 bytes, checksum: 0eec38ed3470ea1ff2f29f63cf555e2b (MD5) Previous issue date: 2014-02-26 / O presente trabalho teve como objetivo caracterizar a qualidade da romã „Molar‟ durante o armazenamento dos frutos in natura, sob diferentes temperaturas de refrigeração, e avaliar o uso de biofilmes à base de fécula de mandioca e Spirulina platensis nos frutos armazenados sob as condições ambiente à 25ºC e sob condições de armazenamento refrigerado a 10ºC. O estudo foi subdividido em duas etapas no Laboratório de Análise de Alimentos da UFCG, no Campus de Pombal - PB. Na primeira etapa, os frutos foram armazenados nas temperaturas 6°C, 10°C e 12°C e analisados ao 0, 12, 18, 24, 30, 36 dias de refrigeração, sendo cada intervalo acrescidos de dois dias de permanência em sala sob condição ambiente (24 ± 2ºC e 43 ± 5% UR), para simular as condições de comercialização (Shelf life). Na segunda etapa, foram selecionados doze frutos para sua caracterização inicial, os outros frutos receberam os seguintes tratamentos: T1 - Testemunha, sem recobrimento; T2 - 1% de fécula de mandioca; T3 - 3% de fécula de mandioca; T4 - 1% de Spirulina platensis; T5 - 3% de Spirulina platensis; T6 - 1% de fécula de mandioca e 1% de Spirulina platensis e T7 - 3% de fécula de mandioca e 3% de Spirulina platensis. Ao receber os tratamentos, os frutos foram separados em dois experimentos para o estabelecimento das condições de armazenamento, onde: Experimento I – Frutos tratados e armazenados em sala climatizada, com controle de temperatura e umidade, simulando condições de comercialização em temperatura ambiente (25,1ºC e 43,3% UR) durante 6 dias e Experimento II - Frutos tratados e refrigerados em B.O.D. (10ºC e 56,7% UR) por um período de 12 dias acrescidos de dois dias de permanência sob condições ambiente (Shelf life). Avaliou-se características biométricas, visuais e físico-químicas. Romãs „Molar‟ armazenadas a 10ºC por 36 dias seguidos de „shelf life‟ de dois dias a 24°C, se mantêm satisfatórias para comercialização in natura, sem prejuízos nos atributos de qualidade biométricos, visuais e físico-químicos. O armazenamento dos frutos a 6ºC proporciona prejuízos na qualidade visual dos frutos devido ao aparecimento de manchas, prejudicando a aparência externa. A temperatura de armazenamento a 12ºC proporciona sintomas de murcha apenas ao final do armazenamento. As temperaturas de armazenamento a 6ºC, 10ºC ou 12ºC podem ser temperaturas apropriadas para o armazenamento de romãs destinadas à indústria, por não prejudicarem os atributos internos de qualidade da romã „Molar‟, especialmente relacionados à integridade das sementes, arilos, rendimento de suco, sólidos solúveis, acidez tituláveis, flavonoides e antocianinas. O revestimento com 1% de fécula de mandioca no armazenamento a 25ºC reuniu boas caracterisiticas biométricas, visuais e físico-químicas para a conservação pós-colhetia da romã; A elevada perda dos diâmetros em frutos armazenados em condição ambiente foi fator limitante na qualidade e vida útil pós-colheita de romã „Molar‟. O revestimento com 3% de fécula de mandioca e com 3% de fécula de mandioca mais 3% de Spirulina plantensis associados à refrigeração apresentaram melhor qualidade biométrica, visual e fisico-química durante os quatorze dias de armazenamento. / The present study aimed to characterize the quality of Pomegranate ' Molar ' during storage of raw fruits under different cooling temperatures and evaluate the use of biofilms based on cassava starch and Spirulina platensis in fruits stored under ambient conditions at 25°C and under conditions of cold storage at 10ºC. The study was divided into two stages at the Laboratory of Food Analysis UFCG, Campus de Pombal - PB. In the first stage , the fruits were stored at temperatures 6°C , 10°C and 12°C and analyzed at 0, 12, 18, 24, 30, 36 days of refrigeration and each range , plus two days of stay in room under ambient conditions (24 ± 2ºC and 43 ± 5% RH) to simulate marketing conditions (Shelf Life). In the second stage, twelve fruits were selected for initial characterization , the other fruits received the following treatments : T1 - control , Uncoated; T2 - 1% of cassava starch ; T3 - 3% of cassava starch ; T4 - 1% of Spirulina platensis; T5 - 3% of Spirulina platensis; T6 - 1 % of cassava starch and 1% Spirulina platensis and T7 - 3 % of cassava starch and 3% Spirulina platensis . Upon receiving the treatments, fruits were separated into two experiments to establish the conditions of storage, where: Experiment I - Fruits processed and stored in a climatic chamber with controlled temperature and humidity conditions simulating marketing at room temperature (25,1ºC and 43,3 % RH) for 6 days and Experiment II - Fruits treated and chilled in BOD (10ºC and 56,7 % RH) for a period of 12 days plus two days under ambient conditions (Shelf Life). It was evaluated biometric, visual and physical- chemical characteristics. Pomegranates 'Molar' stored at 10ºC for 36 days followed by 'shelf life' two days at 24°C, remains satisfactory for fresh fruit market without losses in quality attributes biometric, visual and physical chemistry. The storage of fruits at 6ºC provides visual loss in fruit quality due to the appearance of blemishes, impairing external appearance. The storage temperature to 12ºC provides wilt symptoms only at the end of storage. Storage temperatures to 6°C, 10°C or 12°C may be appropriate temperatures for storage of pomegranates for industry not to harm the internal quality attributes of pomegranate ' Molar ', especially related to integrity seeds, arils, juice yield , solids soluble, titratable acidity, flavonoids and anthocyanins. The coating with 1% of cassava starch in storage at 25ºC has gathered good biometric, visual and physic chemical's characteristic for postharvest conservation pomegranate; The high loss of diameter in fruits stored at ambient condition was a limiting factor in the quality and postharvest pomegranate 'Molar' life. The coating with 3% of cassava starch and 3% of cassava starch 3% Spirulina plantensis associated with refrigeration showed better biometric, visual and physico-chemical quality during storage fourteen days.

The demand for deep fried chips by public and the number of people entering the fast food industry in the form of fast food outlets has increased tremendously. Frying oils are very expensive and are the most important ingredient used in the preparation of fried foods. Due to high oil costs and lack of knowledge, frying oils are used to their maximum. This has resulted in the abuse of deep fried chip cooking oils. The overall quality of the deep fried chip cooking oil used in the South Central Operational Entity of the eThekwini Municipality is not known but abused cooking oils have been identified by Environmental Health Practitioners (EHP's) during routine inspections of fast food outlets. Considering all of the above, the objectives of the proposed research were: (l) Determine the overall prevalence of the use of abused deep fried chip cooking oils at fast food outlets in the South Central Operational Entity of the eThekwini Municipality. (2) Determine in which supervision areas in the South Central Operational Entity the use of abused cooking oil is most prevalent. (3) Determine current/reported practices in preserving the quality of chip oil. (4) Make appropriate recommendations to owner/managers of the fast food outlets and to Environmental Health Practitioners. The study design was observational utilizing a Rapid Epidemiological Assessment (REA) technique, with both a descriptive and analytical component. All fast food outlets making deep fried chips in the South Central Operational Entity registered with the eThekwini Health Department at the time of the study were included in the study population. The Lot Quality Assurance Sampling (LQAS) method was used to determine the overall prevalence of the use of abused oil and to determine supervision areas reached the predetermined service target. A total of 100 fast food outlets were sampled. An oil sample from each fast food outlet, which was taken and sent to a laboratory where an Oxifrit Test was done on every oil sample taken. The Oxifrit Test was the benchmark in this study. EHP's of eThekwini Municipality collected further data by means of an observational checklist and a closed-ended questionnaire, which aimed to establish cooking oil preservation practices. The study revealed that 60 of the outlets had oil that was acceptable whereas 40 had oil that was unacceptable (abused oil). In the multivariate analysis the only factors significantly associated with abused oil were the condition of the fryer and frequency of oil change. Supervision Areas 6, and 4 had more abused deep fried chip cooking oil than average in the South Central Operational Entity. For further prioritization, Supervision Areas 6 and 4 fell below the decision rule for majority of acceptable oil preservation practices, thus Supervision Areas 6 and 4 will be targeted for intervention. Intervention will include education, monitoring and ultimately enforcing the law by EHP's to ensure safe use of deep fried chip cooking oil in the South Central Operational Entity within eThekwini Municipality. / Thesis (M.P.H.)-University of KwaZulu-Natal, 2006.

Thesis (M.Tech.: Biotechnology)-Dept. of Biotechnology, Durban University of Technology, 2007 xi, 114 leaves / Eighteen traditionally leafy vegetables consumed as food or medicinal compounds by a majority of people in the KwaZulu Natal province of South Africa were analysed for the presence of potentially harmful chemicals (antinutrients) and for their toxicity and mutagenicity. The purpose of the study was to determine whether leafy vegetables were safe for human consumption. Chemical analysis showed that none of the vegetables contained cyanogenic glycosides, however all the vegetables contained oxalic acid ranging from 24.1 mg/ml to 798.2 mg/ml with Solanum nigrum, Portulaca oleracea and Mormodica balsamina showing the highest concentrations. Most of the vegetables contained negligible amounts of phytic acid and saponins, except for Momordica balsamina (3.01 mg/ml and 1.83 mg/ml, respectively). Fourteen of the plants contained alkaloids with Portulaca oleracea having the highest content (1.53 g total alkaloids/5 g leaf material). Eight of the plants were found to inhibit trypsin activity. These chemical analyses were carried out in duplicate and the mean and standard deviation were used. The Ames test revealed that none of the leafy vegetables produced a mutagenic frequency above 1, except 10 000 µg/ml organic extract of Senna occidentalis (mutagenecity considered at mutagenic frequency above 2), thus none were considered mutagenic. All 18 organic extracts did not kill off more than 50% brine shrimp and were thus considered non-toxic. On the other hand the aqueous extracts of seven vegetables, namely, Physalis viscosa, Amaranthus dubius, Justicia flava, Bidens pilosa, Senna occidentalis, Chenopodium album and Ceratotheca triloba, killed more than 50% of the shrimp and are thus considered toxic above 100 µg/ml. The MTT assay carried out on the organic extracts indicated that 17 vegetables did not kill off more than 50% of HepG2 cells and were thus considered non-cytotoxic. The aqueous extracts of four vegetables, namely, Justicia flava, Asystasia gangetica, Momordica balsamin and Senna occidentalis, however killed more than 50% of the shrimp and were thus considered cytotoxic above 1 000 µg/ml. It may be concluded from the antinutrient analyses and the bioassays on the 18 vegetables that caution needs to be maintained with the consumption of certain leafy vegetables included in this study, especially Senna occidentalis.