Carotenoids in yellow‐ and red‐fleshed papaya (Carica papaya L)

Vitamin A deficiency is a disorder of public health importance in Sri Lanka. A recent national survey revealed that 36% of preschool children in Sri Lanka have vitamin A deficiency (serum retinol <0.2 µg ml^?1). In view of its well‐established association with child morbidity and mortality, this is a reason for concern. One of the main fruits which has been recommended for prevention of vitamin A deficiency in Sri Lanka is papaya (Carica papaya L). In this study the carotenoid profiles of yellow‐ and red‐fleshed papaya were analysed by medium‐pressure liquid chromatography (MPLC) and UV‐vis spectrophotometry. A section of yellow‐fleshed papaya showed small carotenoid globules dispersed all over the cell, whereas in red‐fleshed papaya the carotenoids were accumulated in one large globule. The major carotenoids of yellow‐fleshed papaya were the provitamin A carotenoids β‐carotene (1.4 ± 0.4 µg g^?1 dry weight (DW)) and β‐cryptoxanthin (15.4 ± 3.3 µg g^?1 DW) and the non‐provitamin A carotenoid ζ‐carotene (15.1 ± 3.4 µg g^?1 DW), corresponding theoretically to 1516 ± 342 µg kg^?1 DW mean retinol equivalent (RE). Red‐fleshed papaya contained the provitamin A carotenoids β‐carotene (7.0 ± 0.7 µg g^?1 DW), β‐cryptoxanthin (16.9 ± 2.9 µg g^?1 DW) and β‐carotene‐5,6‐epoxide (2.9 ± 0.6 µg g^?1 DW), and the non‐provitamin A carotenoids lycopene (11.5 ± 1.8 µg g^?1 DW) and ζ‐carotene (9.9 ± 1.1 µg g^?1 DW), corresponding theoretically to 2815 ± 305 µg kg^?1 DW mean RE. Thus the carotenoid profile and organisation of carotenoids in the cell differ in the two varieties of papaya. This study demonstrates that carotenoids can be successfully separated, identified and quantified using the novel technique of MPLC. Copyright © 2003 Society of Chemical Industry     

Phenolic and carotenoid profiles of papaya fruit (Carica papaya L.) and their contents under low temperature storage

BACKGROUND: Tropical fruits are rich in phenolic and carotenoid compounds, and these are associated with cultivar, pre‐ and postharvest handling factors. The aim of this work was to identify major phenolics and carotenoids in ‘Maradol’ papaya fruit and to investigate their response to storage temperature. RESULTS: Ferulic acid, caffeic acid and rutin were identified in ‘Maradol’ papaya fruit exocarp as the most abundant phenolic compounds, and lycopene, β‐cryptoxanthin and β‐carotene were identified in mesocarp as the major carotenoids. Ranges of contents of ferulic acid (1.33–1.62 g kg^?1 dry weight), caffeic acid (0.46–0.68 g kg^?1 dw) and rutin (0.10–0.16 g kg^?1 dw) were found in papaya fruit, which tend to decrease during ripening at 25 °C. Lycopene (0.0015 to 0.012 g kg^?1 fresh weight) and β‐cryptoxanthin (0.0031 to 0.0080 g kg^?1 fw) were found in fruits stored at 25 °C, which tend to increase during ripening. No significant differences in β‐carotene or rutin contents were observed in relation to storage temperature. CONCLUSION: Phenolics and carotenoids of ‘Maradol’ papaya were influenced by postharvest storage temperature with exception of β‐carotene and rutin. Ripe papaya stored at 25 °C had more carotenoids than those stored at 1 °C. Low (chilling) temperature (1 °C) negatively affected the content of major carotenoids, except β‐carotene, but preserved or increased ferulic and caffeic acids levels, as compared to high (safe) temperature (25 °C). Copyright © 2010 Society of Chemical Industry     

Carotenoid bioaccessibility from nine raw carotenoid-storing fruits and vegetables using an in vitro model

BACKGROUND: Many techniques exist for processing fruits and vegetables. The impact of these processes on nutritional qualities of the food can be considerable, however. Given the benefits of eating raw foods, nutrient sources need to be identified that deliver substantial benefit without cooking. In this study a survey of carotenoid bioaccessibility was carried out in order to additionally evaluate the impact of their distinctive storage structures (chromoplasts) on bioaccessibility. RESULTS: Per cent carotenoid bioaccessibility varied among the nine raw, whole fruits and vegetables evaluated, with values of 1–39% for lycopene, 18–20% for α‐carotene, 7–49% for β‐carotene, 9–59% for lutein, 4–22% for violaxanthin and 47–96% for phytoene. Per 100 g of food, grapefruit and watermelon imparted the most lycopene (69 and 64 µg respectively), carrot the most α‐carotene (559 µg), β‐carotene (1078 µg), lutein (91 µg) and phytoene (23 mg) and mango the most violaxanthin (177 µg). Digestive stability averaged over 80%, except for the xanthophylls, which exhibited a wider and lower range of stabilities. CONCLUSION: These data identify raw food sources for carotenoid bioaccessibilities comparable to those of other foods accomplished by substantial processing. The information presented here also has application in identifying appropriate plant‐breeding goals and optimal sources for commercial carotenoid isolations. Copyright © 2012 Society of Chemical Industry     

Carotenoids in different body components of Indian shrimps

The quantitative and qualitative distribution of carotenoids in different body components of four species of shrimp (Penaeus monodon, Penaeus indicus, Metapenaeus dobsonii and Parapenaeopsis stylifera) harvested from shallow waters off the Indian coast was assessed. The highest total carotenoid contents were observed in the head (153.1 µg g^?1) and carapace (104.7 µg g^?1) of P stylifera, while the body components of P indicus showed the lowest carotenoid levels. Astaxanthin and its mono‐ and diesters were the major carotenoids (63.5–92.2% of total carotenoids) present in the carotenoid extracts from the shrimps, while the extracts contained low levels of β‐carotene and zeaxanthin. The major fatty acids in the carotenoid extracts were palmitic, heptadecanoic, palmitoleic, stearic and oleic acids. Copyright © 2004 Society of Chemical Industry     

Carotenoids in pungent and non‐pungent peppers at various developmental stages grown in the field and glasshouse

Carotenoids in edible portions of plants can provide health benefits to humans. How growing conditions affect levels of carotenoids in pepper fruits as they mature is not well known. Five cvs of bell pepper (Bell Captain, Melody, North Star, Ranger, Red Beauty) and five cvs of pungent‐type peppers (Anaheim, Ancho, Cayenne, Pimento, Red Cherry) were grown in a glasshouse and in the field. Fruits were harvested at the green, turning (50% green) and mature red stages and analysed for levels of the carotenoids β‐cryptoxanthin, α‐carotene, β‐carotene, capsanthin, lutein and zeaxanthin and totals of these carotenoids. Levels of provitamin A: retinol equivalents (RE) were derived from levels of β‐cryptoxanthin, α‐carotene and β‐carotene. Levels of most carotenoids and RE were significantly higher in glasshouse‐grown plants, and most were higher in fruits at the red stage. Fruits of Ancho type had the most β‐cryptoxanthin, α‐carotene, β‐carotene, total carotenoids and RE, while fruits of Red Cherry type had the most capsanthin and zeaxanthin, and fruits of Bell Captain had the most lutein. Interactions of the main effects variables, ie location of production (field vs glasshouse), stage of development and cultivar, indicated differences in patterns of carotenoid levels and RE. The data indicated that growing conditions influenced carotenoid levels. The more consistent and protected conditions in the glasshouse may have caused carotenoid levels to be increased, especially at the red stage. Published in 2002 for SCI by John Wiley & Sons, Ltd     

Analyses of tomato peel and seed byproducts and their use as a source of carotenoids

Commercial tomato canning yields two different byproducts. One is the material that results from peeling tomatoes, while the other results from removing the seeds. The peel byproduct contained 100.8 g protein, 256.4 g ash and 299.4 g acid detergent fiber kg^?1. Ash content was high because the peel byproduct contained 83.8 g kg^?1 sodium as a result of using a sodium hydroxide solution to peel the tomatoes. The seed byproduct contained 202.3 g protein, 51.8 g ash, and 537.9 g acid detergent fiber kg^?1. An amino acid analysis of seeds indicated that approximately 60% of the protein results from amino acids. Both byproducts were analyzed for carotenoid content. The lycopene content of peel byproduct was 734 µg g^?1 of dry material. Significant amounts of lutein, β‐carotene, and cis‐β‐carotene were also present. Seed byproduct contained 130 µg lycopene kg^?1 of dry matter. The content of other carotenoids was approximately half of that present in the peels. Peel and seed byproducts were included at 75 g kg^?1 in hen diets to determine the transfer of carotenoids to the yolk. When fed at this concentration, the lycopene content of dry egg yolk was approximately 0.9 µg g^?1. Approximately 0.1% of the lycopene in peel byproduct and approximately 0.7% of the lycopene in the seed byproduct was transferred from the feed to the yolk. Lycopene appears more similar to carotene than to oxycarotenoids in its transfer to the yolk. Copyright © 2005 Society of Chemical Industry     

Metabolomic Profiling of Carotenoid Constituents in Physalis peruviana During Different Growth Stages by LC‐MS/MS Technology

With the current ongoing changes in global food demands, natural carotenoids are preferred by consumers and are gaining attention among food scientists and producers alike. Metabolomic profiling of carotenoid constituents in Physalis peruviana during distinct on‐tree growth stages was performed with liquid chromatography‐tandem mass spectrometry (LC‐MS/MS) technology. The results show that the β rings of β‐carotene are hydroxylated with great efficiency, and there is a continual synthesis of zeaxanthin at half‐ripe and full‐ripe stages, which is confirmed by relating the zeaxanthin content to that of its precursor (β‐carotene). Lutein was, in terms of mass intensity, the most abundant carotenoid constituent (64.61 µg/g at the half‐ripe stage) observed in this study. In addition, γ‐carotene, which is rare in dietary fruits and vegetables, was detected in the mature and breaker stages, albeit at a relatively low level. The results suggest that when we consider the variation in carotenoid content during different growth stages, Physalis peruviana can be considered a good source of natural carotenoids.     

Screening sweetcorn for enhanced zeaxanthin concentration

BACKGROUND: New varieties of fruits and vegetables, with higher carotenoid levels, are being developed to improve the potential health benefits to consumers. To assist the development of a new variety of high zeaxanthin sweetcorn, an analytical screening method was developed, including chromameter measurement of hue angle and optimized extraction for HPLC, and applied to 385 lines of a breeding population and six commercial varieties. RESULTS: Saponification had no effect on carotenoid extraction. In the breeding population, carotenoid levels had a wide range with the highest levels of zeaxanthin being 11.9 mg kg^?1 fresh weight, which was at least six times greater than the tested commercial varieties. The regression of hue angle versus zeaxanthin was described by the equation, hue angle = 76.16 + 4.50 × exp(?0.24 × zeaxanthin) + 11.73 × exp(?0.24 × zeaxanthin), r² of 0.59. The top 6% of lines, with regards to zeaxanthin (zeaxanthin + β‐cryptoxanthin + β‐carotene) and total carotenoids, all had hue angles ≤84.1°. CONCLUSION: The use of a hue angle of 85° as a maximum cut‐off for liquid extraction will allow for much increased efficiency in screening further germplasm for high zeaxanthin lines. There appears to be significant opportunity to further increase the zeaxanthin concentration by selecting for lines which preferentially channel carotenoid synthesis towards zeaxanthin. Copyright © 2009 Society of Chemical Industry     

Comparative study of fatty acid composition,vitamin E and carotenoid contents of palm oils from four varieties of oil palm from Côte d'Ivoire

BACKGROUND: Fatty acid, tocopherol, tocotrienol and carotene contents were assessed in four oil palm species from the National Centre of Agronomical Research of Côte d'Ivoire, two of which were the basal Lamé (HP1) and Deli (HP2) collections and two of which resulted from crossings between HP1 and HP2 varieties of Eleais guineensis, HP3 and HP4 being identified as the first and second cycle selection, respectively. RESULTS: Palm oil species were characterized by the richness in polyunsaturated fatty acids composition (48–60%) compared to saturated fatty acids (40–52%), especially the first variety, which was from the base collection, and the two hybrids ensuing from crossing. Total carotene content of those varieties was higher and accounted for 832–3575 µg g^?1, and the β‐carotene level (580–2390 µg g^?1) was predominant. Total vitamin E content was 864–1124 µg g^?1, with a notable higher content of tocotrienols, especially γ‐and α‐tocotrienol, ranging from 400 to 515 µg g^?1 and from 238 to 350 µg g^?1, respectively. CONCLUSION: Crossing seemed to be useful in improving the performance and analytical characteristics of the base collection materials. Copyright © 2009 Society of Chemical Industry     

Carotenoid composition of kale as influenced by maturity,season and minimal processing

The principal carotenoids of kale were identified by chemical reactions, high‐performance liquid chromatography/mass spectrometry and high‐performance liquid chromatography/photodiode array detection and were quantified by the last technique. In kale taken from conventional farms, the β‐carotene and lutein contents were significantly higher in the mature leaves, violaxanthin was at an unusually high level in the young leaves, and neoxanthin had practically the same concentration at both stages of maturity. In samples taken from an organic farm, the carotenoid contents were essentially the same in the young and the mature leaves. Except for β‐carotene, which did not differ with season, the carotenoid concentrations of marketed minimally processed kale were found to be significantly higher in the summer than in the winter, reflecting seasonal rather than processing effects. In minimally processed kale monitored during 5 days of storage at 7–9 °C, β‐carotene, lutein, violaxanthin and neoxanthin were reduced by 14, 27, 20 and 31% respectively. Thus minimal processing, seasonal and maturity factors were found to have an influence on the carotenoid content of kale. Copyright © 2004 Society of Chemical Industry     

Antioxidant capacity and secondary metabolites in four species of Andean tuber crops: native potato (Solanum sp.), mashua (Tropaeolum tuberosum Ruiz & Pavón), Oca (Oxalis tuberosa Molina) and ulluco (Ullucus tuberosus Caldas)

Four species of edible tubers endemic to and domesticated in the Andes, native potato (Solanum sp.), mashua (Tropaeolum tuberosum Ruiz & Pavón), oca (Oxalis tuberosa Molina) and ulluco (Ullucus tuberosus Caldas), were studied for their antioxidant capacity and associated secondary metabolites. The antioxidant capacity was measured using ABTS^? radicals and total phenolics, carotenoids, anthocyanin, betaxanthin and betacyanin content were also characterized. The antioxidant capacity found in the crops studied ranged from 483 to 9800 µg trolox equiv. g^?1, phenolics ranged from 0.41 to 3.37 mg chlorogenic acid equiv. g^?1, anthocyanins ranged from 0.08 to 2.05 mg cyanidin 3‐glucoside g^?1 and carotenoids ranged from 1 to 25 µg β‐carotene g^?1. The content of bioactive compounds was high and variable between crops and within the genotypes studied. In general, mashua tubers showed the highest antioxidant capacity and phenolic, anthocyanin and carotenoid content compared with other crops. Ulluco was the only crop that contained betalains in the acid form of betaxanthins (22–96 µg g^?1) and betacyanins (64 µg g^?1) with no presence of carotenoids or anthocyanins. This is the first publication regarding the antioxidant capacity of and associated secondary metabolites in Andean tubers. This information can be useful in the identification of Andean tubers species and genotypes with potential value as a novel dietary source of antioxidants for food, and also for medicinal use. Copyright © 2006 Society of Chemical Industry     

Waste from peach (Prunus persica) processing used for optimisation of carotenoids ethanolic extraction

The processing of peaches to produce fruit pulp generates solid and liquid wastes rich in phytochemicals, such as carotenoids; thus, the objective of this work was to study the use of this waste for carotenoid extraction based on a complete experimental design and using response surface methodology. The parameters studied were the amount of solvent (20–50 mL), the number of extractions (1–5) and the extraction time (10–30 min). The extracts were analysed by spectrophotometry and the optimised conditions by HPLC. The optimised results were four extractions of 10 min using 38.5 mL of ethanol, which presented a yield of 168.59 μg g^?1 DW of total carotenoids of which 67.55 μg g^?1 corresponds to β‐carotene, 86.75 μg g^?1 to cryptoxanthin, 12.08 μg g^?1 to zeaxanthin and 2.2 μg g^?1 to lutein, which representing 66% of extraction pigments relative to the total content of carotenoids present in the peach waste.     

Antioxidant actions and phenolic and vitamin C contents of common Mauritian exotic fruits

Seventeen commonly consumed exotic fruits from Mauritius were analysed for their antioxidant capacity, total phenolics, proanthocyanidins, flavonoids and vitamin C content. Two independent methods were used to evaluate the antioxidant potential of total fruit extracts. The antioxidant activities of the fruits ranged from 1 to 47 µmol Trolox equivalent antioxidant capacity (TEAC) g^?1 fresh weight and from 0.3 to 34 micro/mol g fresh weight (FRAP) g^?1 fresh weight. Total phenolics in the fruits ranged from 118 to 5638 µg g^?1 fresh weight, proanthocyanidins from 7 to 2561 µg g^?1 fresh weight, flavonoids from 21 to 712 µg g^?1 fresh weight and vitamin C content from 8 to 1426 µg g^?1 fresh weight. There were strong correlations between antioxidant activity (assessed by both TEAC and FRAP) and total phenolics and proanthocyanidins. Flavonoids seemed to contribute less to the antioxidant potential of the fruits, while very poor correlations were observed between ascorbate content and antioxidant activity. The highest antioxidant capacities were observed in red and yellow Psidium cattleianum Sabine ‘Chinese guava’, sweet and acid Averrhoa carambola L ‘starfruit’, Syzygium cumini L Skeels ‘jamblon’ and white Psidium guajava L ‘guava’. These fruits were also characterised by high levels of total phenolics. Mauritian exotic fruits are thus a significant source of phenolic antioxidants, which may have potential beneficial effects on health. Copyright © 2003 Society of Chemical Industry     

In vitro accessibility of β‐carotene from cooked Sri Lankan green leafy vegetables and their estimated contribution to vitamin A requirement

Vitamin A deficiency is an important issue for public health in Sri Lanka, where pro‐vitamin A carotenoids from green leafy vegetables provide most of the dietary vitamin A. The objective of this study was to analyse the β‐carotene content of seven types of green leafy vegetables and calculate the contribution of one traditionally cooked portion to the recommended daily allowance (RDA) of retinol. The total amount and in vitro accessibility of β‐carotene were determined using HPLC. The in vitro method simulates the conditions in the human intestinal tract. The all‐trans‐β‐carotene content in the fresh blanched vegetables ranged from 149 µg g^?1 dry weight (DW) in leaves of Alternanthera sessilis (mukunuwanna) to 565 µg g^?1 DW in Amaranthus caudatus (thampala). One portion (100 g) of green leaves cooked without fat (coconut) only contributed from 140 to 180 µg mg^?1 of the recommended daily allowance. A. sessilis, Centella asiatica (gotukola), Spinacea oleracea (nivithi) and A. caudatus, cooked with coconut fat contributed 140–680 µg mg^?1. However, stir‐fried or ‘malluma’ preparations (with coconut products) of Sesbania grandiflora (kathurumurunga) and Manihot esculenta (manioc) may provide more than 1.59–4.37 times the RDA of retinol. These results show that not only the choice of green leaves used but also the addition of fat while cooking is of great importance. Copyright © 2005 Society of Chemical Industry     

Compositional variation in β‐carotene content,carbohydrate and antioxidant enzymes in selected banana cultivars

Banana is one of the most important tropical fruits, and India ranks first in its world production. Banana cultivars rich in provitamin A carotenoids may offer a potential food source for alleviating vitamin A deficiency, particularly in developing countries. With a view to exploit banana peels as a source of valuable components, in the present study, proximate composition, carotenoids, beta‐carotene and some anti‐oxidative enzymes as well as carbohydrate content of selected Indian banana varieties were determined. Karpooravalli cultivar of banana showed the maximum accumulation of carotenoid content in the non‐edible (68 μg g^?1 d.w.) portion of banana, while being the second highest in beta‐carotene content (143.12 μg per 100 g). However, Red Banana ranked highest in total carotenoid contents for pulp (4 μg g^?1 d.w.) and beta‐carotene was estimated to be the highest in the case of peels (241.91 μg per 100 g) and in pulp (117.2 μg per 100 g). Karpooravalli cultivar of banana is also rich in carbohydrate content in terms of total starch (1786.0 μg g^?1 d.w. in peels and 544.85 μg g^?1 d.w. in pulp) and sugars (53.53 μg g^?1 d.w. in peels and 39.05 μg g^?1 d.w. in pulp). The catalase enzyme activity in these peels ranged from 5.66 to 35.57 nmol min^?1 mg^?1 proteins and was found at a higher level in cultivar Poovan, while the ascorbate peroxidase showed the range of 2.25 to 6.22 μmol min^?1 mg^?1 proteins. The peels of cultivars Red Banana and Karpooravalli are rich source of bioactive compounds, such as carotenoids (beta‐carotene), anti‐oxidative enzymes and carbohydrate contents.     

Possible nutritional and health‐related value promotion in orange juice preserved by high‐pressure treatment

Effects of high‐pressure treatment on the orange juice carotenoids (β‐carotene, α‐carotene, zeaxanthin, lutein and β‐cryptoxanthin) associated with nutritional (vitamin A) and health‐related (radical‐scavenging capacity) values were investigated. Various high‐pressure treatments (50–350 MPa) combined with different temperatures (30 and 60 °C) and times (2.5, 5 and 15 min) of treatment were assayed. The carotenoid content of the orange juice was analysed by HPLC‐UV, the vitamin A value was determined as retinol equivalents (RE) and the free radical‐scavenging capacity was evaluated using the DPPH (2,2‐diphenyl‐1,1‐picrylhydrazyl) radical model system. A storage study was carried out at refrigeration temperature (4 °C). High‐pressure treatments at 350 MPa produced significant increases of 20–43% in the carotenoid content of fresh orange juice (from 3.99 to 4.78–5.70 mg l^?1). A non‐uniform behaviour of high‐pressure treatments was detected. An increase in time (beyond 5 min) or temperature (above 30 °C) of treatment did not improve the amount of carotenoids extracted. Owing to better extraction of carotenoids, an increase in vitamin A value from 164 to 238 RE l^?1 (45%) was achieved with the 350 MPa/30 °C/5 min treatment. No correlation was found between the increase in carotenoid amount extracted and the free radical‐scavenging activity. © 2002 Society of Chemical Industry     

A proposed mechanism for the inhibition of soybean lipoxygenase by β‐carotene

The inhibition mechanism of soybean lipoxygenase (LOX) by β‐carotene was studied. Addition of β‐carotene into the reaction mixture decreased the rate of conjugated diene formation. Increasing the concentration of β‐carotene in the reaction mixture resulted in a decrease in the rate of conjugated diene formation. Although the rate of conjugated diene formation was lower in the presence of β‐carotene, the same amounts of linoleic acid hydroperoxides were formed by the enzyme at the end of the reaction, both with and without β‐carotene in the reaction medium. The rates of conjugated diene formation for 40, 20, 10 and 4 U mL^?1 LOX enzyme were almost equal to zero when the concentrations of β‐carotene were 20, 17.5, 15 and 10 µmol L^?1 in model reaction systems, respectively. β‐Carotene directly influences the amount of enzyme in the reaction medium available for the catalytic conversion of linoleic acid into corresponding hydroperoxides. The results obtained here suggest that β‐carotene reacts with linoleyl radical (L^?) at the beginning of the chain reaction, preventing the accumulation of conjugated diene forms (LOO^?, LOO^? and LOOH). Since L^? transforms back to its original form of LH, the enzyme cannot complete the chain reaction and thus remains at inactive Fe(II) form. Copyright © 2005 Society of Chemical Industry     

Pigments in Greek virgin olive oils: occurrence and levels

Fifty‐two samples of virgin olive oil from various regions of Greece were examined for the presence and levels of chlorophyll and carotenoid pigments using normal phase liquid chromatography and spectrometry. Pheophytin α (Pheo α) was the main pigment in all the oils examined (>10 mg kg^?1 in more than 70% of samples). Two pheophytin α derivatives (peaks A and B), eluted close to Pheo α, may potentially be used to examine handling conditions and length of storage of oil until analysis. Analysis of 25 Greek commercial oils obtained from retail stores verified the above observations. Chlorophyll α may be present in a virgin olive oil just after production. Its absence should not be exclusively attributed to cultivar characteristics or extraction conditions, since pheophytinisation occurs rapidly. Lutein content varied between 0.2 and 3.9 mg kg^?1 and β‐carotene content from 0.4 to 5.1 mg kg^?1. The lutein/β‐carotene ratio was characteristic (<1) for samples from Koroneiki, the major Greek cultivar for oil production. The total Pheo α (Pheo α + peak A + peak B)/total carotenoid (lutein + β‐carotene) ratio ranged between 2 and 11 owing to prevailing green hues. This ratio may be used as an indicator of oil typicality along with other analytical parameters. © 2001 Society of Chemical Industry     

Controlled‐atmosphere storage of tomato fruit: low oxygen or elevated carbon dioxide levels alter galactosidase activity and inhibit exogenous ethylene action

The effects of 3% O₂ and 20% CO₂, both alone and together with 100 µg g⁻¹ C₂H₄, on ethylene production, chlorophyll degradation, carotenoid biosynthesis and α‐ and β‐galactosidase activity in breaker tomato (Lycopersicon esculentum Mill) fruit were investigated. The low O₂ and high CO₂ atmospheres prevented the rise in ethylene production, total carotenoid and lycopene biosynthesis and α‐ and β‐galactosidase activity and slowed down chlorophyll degradation and loss of firmness (P < 0.05). These suppressive effects were not reversed, or only in part – in the case of chlorophyll breakdown – by addition of 100 µg g⁻¹ C₂H₄ to said controlled atmospheres. After transfer from the various atmospheres to air, flesh firmness decreased and ethylene production, total carotenoids, lycopene and β‐galactosidase II activity increased but these parameters were, in all cases, still significantly different from those of fruit held in air. Keeping tomatoes in controlled atmospheres, even in the presence of ethylene, had marked residual effects. Results suggest an antagonism between elevated CO₂/low O₂ and exogenous ethylene which could determine most of the ripening parameter behaviour under controlled‐atmosphere storage, though a direct regulatory mechanism by O₂ and/or CO₂ should not be discarded. © 1999 Society of Chemical Industry     

Effect of pretreatments and drying temperatures on sweet potato flour

Effect of pretreatments with 1 w/v% sodium hydrogen sulphite (NaHSO₃) and 1 w/v% calcium chloride (CaCl₂) and drying temperatures (55, 60 and 65 °C) on sweet potato flour were investigated. Flour treated with CaCl₂ had higher amounts of ascorbic acid and β‐carotene (10.61–12.54 and 3.26–3.46 mg 100 g^?1 wet basis, respectively) than that treated with NaHSO₃ (9.47–11.47 and 3.05–3.43 mg 100 g^?1 wet basis, respectively). Total phenolic content and water absorption index (wet basis) were highest at 65 °C when treated with NaHSO₃ (10.44 mg 100 g^?1 and 2.49 g g^?1 respectively) and CaCl₂ (9.52 mg 100 g^?1 and 2.85 g g^?1 respectively). Swelling capacity (wet basis) was highest at 60 °C when treated with CaCl₂ (2.96 g g^?1) whereas when treated with NaHSO₃ (2.85 g g^?1) it was highest at 55 °C. Freeze‐dried samples treated with NaHSO₃ had higher lightness and total phenolic content while CaCl₂‐treated samples had higher β‐carotene and ascorbic acid. The results showed that good quality flour could be produced after soaking in CaCl₂ and dried at 65 °C.