Characterisation of avocado (Persea americana Mill) honeys by their physicochemical characteristics

The quality of 12 avocado (Persea americana Mill) honeys from Spain was evaluated. Eight common physicochemical parameters were analysed, namely water content, pH, acidity (free, lactonic and total), sugar content, ash content and electrical conductivity. In addition, the honey samples were analysed using inductively coupled plasma optical emission spectrometry (ICP‐OES), and six minerals were quantified for each honey, namely potassium (K), calcium (Ca), magnesium (Mg), sodium (Na), phosphorus (P) and sulphur (S). Most samples showed proper maturity considering the medium water content (mean 17.7%). The total acidity (below 50 meq kg^?1 except for one sample) indicated absence of undesirable fermentation; also, the mean pH of around 4.77 is usual in this kind of honey. The values for ash content and electrical conductivity were high (0.77% and 798 µS cm^?1 respectively) and typical of dark honeys. K was the predominant mineral (accounting for 73% of the total minerals quantified), followed by Na (10%). Copyright © 2004 Society of Chemical Industry     

Volatile components of avocado leaves (Persea americana mill) from the Mexican race

The chemical composition of the volatile oil of avocado leaves from Mexican race (Persea americana Mill) grown in the highlands of Mexico was investigated by gas chromatography and gas chromatography-mass spectrometry. Thirty compounds were identified accounting for 92.45% of the oil. Estragol (78.12%), α-cubebene (3.58%), methyl eugenol (3.37%) and β-caryophyllene (2.10%) were the major components representing more than 87%. The oil has a characteristic aroma similar to anise-tobacco.     

Enzymatic browning in avocado (Persea americana) revisited: History,advances, and future perspectives

Considering nearly 80 years of research regarding one of the enzymes responsible for catalyzing the formation of pigments in higher animals, plants, fungi and bacteria, this review will focus on collecting and categorizing the existing information about polyphenol oxidase (PPO) in fruits, with particular emphasis on the information in relation to avocado, which is one of the hardiest species in terms of inactivation, has documented dual activity (EC 1.14.18.1/EC 1.10.3.1), and represents one of the oldest challenges for food science research and fruit processors.

It is expected that this review will contribute to the further development of the field by highlighting the questions that have arisen during the characterization of PPO, the progress that has been made and the questions that remain today, in addition to new methodologies that are being applied to study this system. Holistic methodologies offer unexplored potential for advancing our understanding of the complex phenomena that govern PPO activity in fruits, because these methodologies will enable the characterization of this family of enzymes in all of its complexity. Subsequently, it will be possible to develop better techniques for controlling enzymatic browning in this valuable fruit.     

Laboratory preparation and evaluation of Pollock variety avocado (Persea americana Mill) guacamole

Guacamole was produced from ripe avocado (Persea americana) by blending the pulp with local herbs, spices and salt. The guacamole was stored at 5 °C for 2 weeks, during which physical, chemical and microbial analyses were conducted. Organoleptic evaluations by a semi‐trained panel were also performed, until the guacamole was deemed unfit for human consumption. The results indicated that fresh avocado pulp contains 835, 13, 16, 92, 44, 16 and 0.078 g kg^?1, moisture, ash, protein, fat, carbohydrate, fiber, and vitamin C respectively, and has a pH of 6.7; compared with 838, 13, 16, 92, 44, 16, and 0.042 g kg^?1, respectively, of the same nutrients in freshly prepared guacamole, which has a pH of 6.0. During storage, the moisture content, consistency, total soluble solids and total titratable acidity (as citric acid) of the guacamole increased, but the vitamin C content decreased. The color of the avocado pulp, which darkened during conversion into guacamole, darkened further as storage increased as evidenced by a decrease in the L, a and b values. Sensory evaluation revealed that the mean storage period (5 °C) for the guacamole was 6 days. Although the fresh avocado pulp, the freshly prepared guacamole, and the stored guacamole contained bacteria, yeasts and molds, the pathogens Staphylococcus aureus and Salmonella were absent. Copyright © 2007 Society of Chemical Industry     

Quality evaluation of broom honey (Spartocytisus supranubius L) produced in Tenerife (The Canary Islands)

The qualities of 24 samples of broom (Spartocytisus supranubius L) honey from Mount Teide National Park (Tenerife) were evaluated. A total of 33 pollen types was identified. The study demonstrated the predominance of Spartocytisus supranubius, and minor incidence of Echium wildpretii, Descurainia bourgaeana, Erysimum scoparium and Pteocephalus lasiospermus, which are major edemic plants of this zone. The low electrical conductivity was typical of pale honeys. Most samples showed a proper maturity indicated by the low water content. Since the hydroxymethylfurfural content was also low, good freshness was indicated. The free acidity (below 16.8 meq kg^?1) indicated the absence of undesirable fermentation, and the mean pH (around 3.89) is usual for this kind of honey. The fructose/glucose ratio was 1.29 ± 0.07 and sucrose content averaged 9.9 ± 9.3 g kg^?1, with significance presence of erlose (24.4 ± 16.8 g kg^?1). Among the 12 organic acids detected, gluconic, isobutyric and butyric acids were identified in the majority of samples at high concentrations. Malic acid which was also present can be used as an marker for the differentiation of broom honey. Copyright © 2004 Society of Chemical Industry     

Quantitative evaluation of the phenolic profile in fruits of six avocado (Persea americana) cultivars by ultra-high-performance liquid chromatography-heated electrospray-mass spectrometry

The phenolic profiles of six varieties of avocado (Persea americana) grown in Sicily were investigated. The ultra-high-performance liquid chromatography-heated electrospray-mass spectrometry method was developed to determine qualitative and quantitative changes in fruits at two different ripening stage. Nineteen individual phenolic compounds were detected in avocado pulp extracts. Gallic acid, sinapinic acid, vanillin, p-coumaric acid, and gentisic acid were present only in ripe fruits. On the contrary, epicatechin decreased with fruit ripening, whereas protocatechuic acid, 4-hydroxybenzoic acid, chlorogenic acid, and benzoic acid were relatively stable or exhibited erratic changes with fruit ripening. The different avocado cultivars exhibited different phenolic profiles and total quantities and it was found that, among the tested cultivars, “Orotawa” avocados may provide the highest nutritional and health contribution to human diet. The qualitative and quantitative differences among cultivars and maturation stages by multivariate analysis allowed for the individuation of a set of phenolic compounds that have a great potential in the discrimination and identification of different genetic groups.     

Partial purification and enzymatic characterization of avocado (Persea americana Mill,cv. Hass) lipoxygenase

Detrimental effects on minimally processed fruits and vegetables induced by increased lipoxygenase (LOX) activity are a major concern in the food industry. Partial purification and enzymatic characterization of lipoxygenase (LOX) from avocado fruit (Persea americana Mill, cv. Hass) is presented. Avocado LOX was partially purified by fractional precipitation with ammonium sulfate, followed by anion exchange adsorption. Substrate specificity and effects of temperature, pH and calcium ion concentration on LOX activity were determined. Likewise, the in vitro ability of avocado LOX to co-oxidize β-carotene was determined. LOX showed a higher substrate affinity for linolenic than for linoleic acid. Optimum activity was reached at 40 °C, pH 6.5, and 0.20 mM of calcium ion concentration. Avocado LOX showed β-carotene co-oxidation capability. Considering the optimums and operational ranges established for each studied factor, strategies concerning the inactivation of LOX may be proposed to reduce the detrimental effects on minimally processed avocado products. Additionally, the co-oxidation capability of avocado LOX may be of interest for the avocado industry due to its potential application as a bleaching agent.     

Gelatine–starch films: Physicochemical properties and their application in extending the post‐harvest shelf life of avocado (Persea americana)

BACKGROUND: Several storage techniques have been developed to extend the post‐harvest shelf life of horticultural products. One method involves the use of edible or biodegradable coatings. Such coatings are made of biological materials that are used to coat fresh products, providing a semi‐permeable barrier to water vapour and gases, e.g. O₂ and CO₂. The influence of starch concentration, glycerol content and pH on the carbon dioxide permeability (CO₂P) and mechanical properties of gelatine–starch edible films were evaluated. RESULTS: Results showed that increments in the starch concentration and pH resulted in higher CO₂P values. Film puncture strength increased when the starch concentration decreased and the maximum resistance value (32.6 N) was obtained at pH 6. Deformation was mainly affected by glycerol and starch content. Some films were chosen in order to evaluate their effect, as coatings, in the post‐harvest shelf life of avocados (Persea americana Mill c.v. Hass). Fruits were immersed in the coating solutions, air dried and stored at two temperatures. Changes in colour, weight loss and pulp firmness were determined in fruits stored at 6 °C. In addition, respiration rate was measured in avocados kept at 20 °C. CONCLUSION: The application of gelatine–starch coatings delayed the ripening process of avocados, as indicated by a better pulp firmness and retention of skin colour, and lower weight loss of coated fruits in comparison with control avocados. The coatings also resulted in a delayed respiratory climacteric pattern, by 3 days, for coated fruits. Copyright © 2007 Society of Chemical Industry     

Correlation between methyl anthranilate level and percentage of pollen in Spanish citrus honey

The common level of methyl anthranilate (MA) in Spanish citrus honey and the correlation between this compound and the percentage of citrus pollen (sometimes underrepresented) are evaluated. The MA analysis methodology was validated before analysing the honeys (harvested in 2011 and 2012), which were characterised by pollen, MA, hydroxymethylfurfural, electrical conductivity, moisture and colour. Pollen ranged 1–88% and MA 0.5–5.9 mg kg^?1, and there was no quantitative correlation between both. However, significant correlations with moderate Pearson coefficients were observed: MA/electrical conductivity (?0.678); MA/colour (?0.559); pollen/electrical conductivity (?0.553); and pollen/colour (?0.556). 89.2% of samples from 2011 and 95.4% from 2012 had the required level of citrus pollen (at least 10%), although only 53.5% and 61.4%, respectively, had the commercially required level of MA (2 mg kg^?1). Only about half of the samples satisfied both parameters. The MA value should be recommended only when the honey has an unexpectedly low percentage of citrus pollen, and after assessing organoleptic and physicochemical parameters.     

Palynological,physico‐chemical and organoleptic characteristics of carob tree (Ceratonia siliqua L.) honey from Sicily

This study shows the results of melissopalynological and sensory evaluations on twenty‐five carob tree honey samples coming from Sicily and declared unifloral by the local beekeepers. This specific carob tree honey production is erratic and limited because of its cold weather spreading, depending on seasonal trends that influence both the final amount and quality of honey itself. According to the melissopalynological results on samples, a minimum of 15% carob tree pollen was considered sufficient to typify these honeys as unifloral. The physico‐chemical analysis was performed on the samples satisfying this percentage and determined the following parameters: moisture, pH, acidity, HMF, diastase activity, electrical conductivity, ash, sugar and colour. Physico‐chemical analyses showed medium to high values for diastase activity, electrical conductivity, free acidity and moisture.     

Antioxidant properties and phenolic content of sulla (Hedysarum spp.) honeys from Southern Italy

The geographical origin greatly influences the qualitative and nutraceutical characteristics of honey. In this study, a total of twenty‐four sulla honeys from eight different geographical areas of Southern Italy have been examined for total phenolic content (Folin–Ciocalteu method), antioxidant activity (FRAP and DPPH assays), colour intensity (ABS₄₅₀), and identification and quantification of phenolic acids (RP‐HPLC/UV‐VIS method). The total phenolic content ranged from 47.9 (Potentino honeys) to 248.3 mg GAE per kg honey (Penisola Sorrentina honeys). The antioxidant activity ranged from 47.06% (Basso Pollino honeys) to 88.25% (Penisola Sorrentina honeys), and from 98.26 μM Fe (II) (Potentino honeys) to 786.53 μm Fe (II) (Tarantino honeys) for DPPH and FRAP assays, respectively. Major phenolic acids identified in analysed samples were gallic, caffeic and ferulic acids. Correlations between the parameters analysed were statistically significant (P < 0.05). The results of the study showed that the parameters studied are greatly affected by the peculiarities of their production area.     

Physical properties,chemical characterization and fatty acid composition of Mexican chia (Salvia hispanica L.) seeds

Chia seeds were utilized by Aztecs as food and for medicinal purposes. Nowadays, this crop is gaining importance in many countries, due to its nutritional attributes. Some physical properties and chemical characteristics of chia seeds from four different regions of Mexico were evaluated and compared. Seed size distribution was not significantly affected (P > 0.05) by the region, with similar values of seed length (2.03–2.10 mm), width (1.27–1.32 mm), thickness (0.77–0.81 mm) and surface area (4.95–5.42 mm²). Bulk density (662–741 kg m^?3), geometry and granulometric distribution were also determined. Origin of tested seeds significantly (P < 0.05) influenced their composition; all seeds had high contents of protein (18.5–22.3%), fat (21.5–32.7%) and fibre (20.1–36.1%). Chia seeds ratio between omega‐3 and omega‐6 fatty acids was 3:1 for the studied regions; seeds from Chiapas and Michoacán had the highest proportion of ω‐6 and ω‐3 fatty acids. The studied seeds contained phenolic compounds in the range of 0.53–0.71 mg GAE g^?1.     

Cagaita (Eugenia dysenterica DC.) of the Cerrado of Minas Gerais, Brazil: Physical and chemical characterization, carotenoids and vitamins

The physical characteristics (diameters, height and mass), chemical composition (tritratable acidity, soluble solids, pH, moisture, ash, protein, lipids and total dietary fiber), occurrence and content of vitamin C (ascorbic acid and dehydroascorbic acid), carotenoids (??-carotene, ??-carotene, ??-cryptoxanthin and lycopene), vitamin E (??-, ??-, ??- and ??-tocopherol and tocotrienol) and folates (tetrahydrofolate, 5-methyltetrahydrofolate and 5-formyltetrahydrofolate) were evaluated in the cagaita obtained from the Cerrado of Minas Gerais, Brazil. The analyses of vitamin C and carotenoids were performed by HPLC-DAD and vitamin E and folates by HPLC with fluorescence detection. The cagaita pulp presented high content of moisture (91.56 g 100 g^− 1), vitamin C (34.11 mg 100 g^− 1) and folates (25.74 ??g 100 g^− 1). The presence of protein (0.63 g 100 g^− 1), ash (0.18 g 100 g^− 1), lipids (0.57 g 100 g^− 1), carbohydrates (5.54 g 100 g^− 1), dietary fiber (1.54 g 100 g^− 1) and carotenoids (0.77 mg 100 g^− 1) was observed in its composition. Vitamin E isomers were not detected. Consumption of cagaita (100 g) contributed significantly to supply the daily requirements of vitamin C (on average 71.0%), vitamin A (on average 7.5%) and folates (on average 7.9%). The cagaita showed high pulp yield, reduced total energy value and was considered a source of vitamin C, which play important role in human health.