Image Processing Applied to Classification of Avocado Variety Hass (Persea americana Mill.) During the Ripening Process

This work was undertaken to analyze the ripening process of avocados variety Hass (Persea americana Mill.) by image processing (IP) methodology. A set of avocados (10 samples) was used to follow the changes in image features during ripening by applying a computer vision system, extracting color and textural parameters. Other 16 avocados were used to evaluate the firmness and mass loss. Three maturity stages of avocados were established, and a classification was obtained by applying principal component analysis and k-nearest neighbor algorithm. During the ripening process (12 days), avocado firmness decreased from 75.43 to 2.63 N, while skin color values kept invariable during 6 days; after that, a decrement in the peel green color (a*) was observed (−9.68 to 2.32). Image features showed that during ripening the color parameters (L*, a*, and b*), entropy (4.29 to 4.00), angular second moment (0.287 to 0.360), and fractal dimension (2.58 to 2.44) had a similar path as compared to mass loss, a*, and firmness ripening parameters, respectively. Relationships between image features and ripening parameters were obtained. The parameter a* was the most useful digital feature to establish an acceptable percentage of avocado classification (>80%) in three different maturity stages found. Results obtained by means of IP could be useful to evaluate, at laboratory level, the ripening process of the avocados.     

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.     

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.     

Physical, chemical and palynological characterization of avocado (Persea americana Mill.) honey in Israel

Various methods were used to characterize avocado honey in Israel. Perseitol, a unique sugar present only in avocado honey, served as an indicator for the degree of purity of avocado honey. Low avocado pollen counts made the common melissopalynology method ineffective at predicting the contribution of avocado nectar to honey. It was also found that the levels of fructose, sucrose and glucose do not uniquely characterize avocado honey. Potassium content and eight other minerals were linearly highly correlated to perseitol content. Moreover, pH level, absorbance and degree of darkness were significantly correlated to perseitol content, and can therefore be used to characterize avocado honey.     

Effect of pepper tree (Schinus molle) essential oil-loaded chitosan bio-nanocomposites on postharvest control of Colletotrichum gloeosporioides and quality evaluations in avocado (Persea americana) cv. Hass

Food Science and Biotechnology - Preventive and curative activity of postharvest treatments with chitosan nanoparticles (CS) and chitosan biocomposites loaded with pepper tree essential oil...     

Reduction of Salmonella enterica, Escherichia coli O157:H7, and Listeria monocytogenes with electrolyzed oxidizing water on inoculated hass avocados (Persea americana var. Hass)

This study was intended to evaluate the bactericidal effect of electrolyzed oxidizing water (EOW) and chlorinated water on populations of Salmonella enterica, Escherichia coli O157:H7, and Listeria monocytogenes inoculated on avocados (Persea americana var. Hass). In the first experiment, inoculated avocados were treated with a water wash applied by spraying tap water containing 1 mg/liter free chlorine for 15 s (WW); WW treatment and then spraying sodium hypochlorite in water containing 75 mg/liter free chlorine for 15 s (Cl75); WW treatment and then spraying alkaline EOW for 30 s (AkEW) and then spraying acid EOW (AcEW) for 15 s; and spraying AkEW and then AcEW. In another experiment, the inoculated avocados were treated by spraying AkEW and then AcEW for 15, 30, 60, or 90 s. All three pathogen populations were lowered between 3.6 and 3.8 log cycles after WW treatment. The application of Cl75 did not produce any further reduction in counts, whereas AkEW and then AcEW treatment resulted in significantly lower bacterial counts for L. monocytogenes and E. coli O157:H7 but not for Salmonella. Treatments with AkEW and then AcEW produced a significant decrease in L. monocytogenes, Salmonella, and E. coli O157:H7 populations, with estimated log reductions of 3.9 to 5.2, 5.1 to 5.9, and 4.2 to 4.9 log CFU/cm2, respectively. Spraying AcEW for more than 15 s did not produce any further decrease in counts of Salmonella or E. coli O157:H7, whereas L. monocytogenes counts were significantly lower after spraying AcEW for 60 s. Applying AkEW and then AcEW for 15 or 30 s seems to be an effective alternative to reduce bacterial pathogens on avocado surfaces.     

Preliminary Studies on Composition,Quality and Oxidative Stability of Commercial Avocado Oil Produced in Chile

Avocado oil is a relatively new oil in the market and is highly appreciated by the consumers because of its fine aroma, pleasant taste and health benefits. A study on the characterization of commercial avocado oils produced in Chile was conducted in order to discuss their quality parameters. The study was applied to two marketed avocado oils. The main analytical parameters evaluated to the oils were： fatty acid composition, total chlorophylls, total carotenoids, tocopherols, acid value, peroxide value, total phenolic compounds, polar compounds, oil stability, UV absorption and 3.5-stigmastadiene content. The fatty acid compositions of the studied oils were according with oil composition of pulp pure of avocado fruit. The analysis of tocopherols by high performance liquid chromatography （HPLC） revealed significant differences between the avocado oils studied. Total phenolic compounds, oil stability, UV Absorption characteristics, peroxide value, acid value, tocopherols content, total chlorophylls, total carotenoids and polar compounds were also significantly different between the commercial studied oils. All the above results show a different quality between both commercial avocado oils, showing that the sample C has worse values for the parameters of quality as those required by legislation in many countries. Also, 3.5-stigmastadiene content shows high concentration for one of the commercial avocado oil evaluated which demonstrates the presence of refined oil or that the oil has been submitted to high temperatures. On the other hand it is remarkable that despite the fact that there are many differences in quality parameters, both oils are labeled and marketed as extra virgin quality oils, demonstrating the need to regulate the classification of appreciated oils by the consumers.     

浅谈奇石与动物（三）

蛙的性格它平时很隐蔽,甚至可以被视为泥土,但它确实存在。你可能瞅不到扑捉蚊虫的瞬间,你总能听到它早晚的叫喊。它不羡慕鸟儿飞得高,也不羡慕鱼儿在水中自由自在,它只相信自己,看准了就出手,势在必得。     

浅谈奇石与动物(二)

小狐仙在这对高大的巴林紫云石对章上,一只完美的狐狸头出现在上部正中,藏者称其小狐仙。关于狐仙的故事有好多。让我最难忘的是葫芦岛市莲花山圣水寺的狐仙洞。     

Characterization and application of a coating of starch extracted from avocado (Persea americana L. cv. Hass) seeds as an alternative to reduce acrylamide content in French fries

Food Science and Biotechnology - The starch extracted from avocado (Persea americana L. cv. Hass) seeds was characterized and used in the preparation of an edible coating to reduce the oil uptake...     

Fatty Acids in the American Groundnut (Apios americana)

The fatty acid profiles of lipids extracted from groundnut (Apios americana Medikus) seeds and tubers were analyzed using gas-liquid chromatography. Groundnut seeds contained 12.1–18.4% lipids and groundnut tubers 4.1–4.6%, on a dry weight basis. Fatty acid profiles of seed and tuber lipids differred; however, linoleic acid predominated. The fatty acid profiles of seeds and tubers varied between plants collected in two different locations, suggesting genetic variability.     

Amino Acids in the American Groundnut (Apios americana)

The amino acid composition of groundnut (Apios americana Medikus) was analyzed using ion-exchange column chromatography. Aspartic and glutamic acids were the predominant amino acids in both seeds and tubers. Other amino acids present in significant quantities were leucine, histidine and proline. The most abundant free amino acids, other than aspartic and glutamic acids, were arginine and leucine in the seeds and histidine and serine in the tubers.     

Histochemical,Biochemical and Ultrastructural Studies on the Liver of Fasted Rats

The subjection of rats with body weight 150 ± 10 g to complete starvation for a period of four days leads to a diminution of total protein, total lipids, blood sugar, body weight and liver weight. Lipid dystrophy develops in the liver, as well as deposition of lipofuscin-like pigment and atrophy. Lipid dystrophy and deposition of pigment increase during the first three days and abruptly decrease during the fourth. Atrophy is a progressive process. The delineation of three phases in the atrophic — dystrophic process is possible with the application of histological, enzyme-histochemical, morphometric, biochemical and electron microscopic methods: Phase I (first 24 hours) — a common adaptive phase. It engages both the liver, which must utilize the increased nutrients from the organism depots and the homeostatic mechanisms of the organism as a whole. Phase II — (second and third 24 hours) — alterative-restorative, manifested markedly at the liver parenchimal level and especially by autophagic lysosome function. Phase III — (fourth 24 hours) — alterative. Exhaustion of adaptive-restorative liver process (and the hepatocyte in particular), and the organism as a whole as well.     

米团花色素的毒理学研究

采用热水提取，获得色价为1040U／mL的米团花色素，利用小鼠进行急性毒性（LD50）、微核试验、精子畸变和Ames试验等毒理学试验项目。结果表明：雌雄小鼠LD50〉21．5g/kgBW，属无毒级物质；2.50～10．0g／kg BW剂量的微核试验和精子畸变试验结果为阴性，受试物对体细胞和生殖细胞无诱变作用；Ames试验结果为阴性，受试物无直接或间接的致突变作用。     

Evaluation of Chemical Properties of Mistletoe Leaves from Three Different Trees (Avocado,African Oil Bean and Kola)

A comparative evaluation of the chemical composition of mistletoe leaves (Viscum album) growing on three different trees: avocado pear (Persea Americana), African oil bean (Pentaclethra macrophylla) and kola (Kola nitida) was undertaken. Fresh mistletoe leaves were obtained from the three different trees and thoroughly washed with water after which they were dried at room temperature (28 ± 1 °C) for 18 days during the dry season (December). After, the dried leaves were shredded and packaged. The samples were then subjected to phyto-chemical, vitamin and mineral analyses using standard methods of analyses. Anthocyanins ranged between 0.3.4 ± 0.003 and 0.37 ± 0.181 mg/g, Tannin, 2.09 ± 1.141 and 3.24 ± 0.003 mg/g, Chlorophyll a, 0.38 ± 0.004 and 0.39 ± 0.018 mg/g, Chlorophyll b 0.52 ± 0.120 and 0.60 ± 0.001 mg/g. Vitamin B1 ranged between 0.85 ± 0.038 and 0.94 ± 0.001 mg/g, Vitamin B2, 0.55 ± 0.007 and 0.61 ± 0.003 mg/g, Vitamin C, 0.77 ± 0.003 and 1.98 ± 0.003 mg/g, Folate 0.53 ± 0.004 and 0.58 ± 0.004 mg/g, Magnesium ranged between 0.21 ± 0.002 and 0.92 ± 0.003 mg/g, Calcium 2.14 ± 0.004 and 2.26 ± 0.001 mg/g, Sodium 0.01 ± 0.000. Iron, 1.24 ± 0.005 and 1.42 ± 0.006 mg/g. Sample obtained from oil bean tree showed lower and differed significantly (p < 0.05) in Anthocyanin and Chlorophyll b with samples obtained from avocado and kola trees. The sample obtained from avocado tree showed higher Tannin content compared with samples obtained from oil bean and kola trees (P ≤ 0.05). There were significant differences (P < 0.05) between the samples in all the vitamins. The minerals showed significant differences in the samples (P < 0.05) except in sodium content which was very low in all the samples. Mistletoe leaves are shown to have a rich chemical composition and could thus serve as a source of these phyto-chemicals, vitamins and minerals.     

Biochemical,microbiological, and nutritional aspects of kimchi (Korean fermented vegetable products)

Kimchi is a traditional, fermented Korean food that is prepared through a series of processes, including pretreatment of oriental cabbage (or radish), brining, blending with various spices and other ingredients, and fermentation. The characteristics of kimchi differ depending on the kimchi varieties, raw materials used, process, fermentation, and preservation methods. However, kimchi has typical biochemical, nutritional, and organoleptic properties and health‐related functions. Kimchi fermentation is initiated by various microorganisms originally present in the raw materials, but the fermentation is gradually dominated by lactic acid bacteria. Numerous physicochemical and biological factors influence the fermentation, growth, and sequential appearance of principal microorganisms involved in the fermentation. Complex biochemical changes occur depending on the environmental conditions before, during, and after fermentation. The most important characteristics are the compositional changes of sugars and vitamins (especially ascorbic acid), formation and accumulation of organic acids, and texture degradation and softening. Nutritionally, kimchi is an important source of vitamins, minerals, dietary fiber, and other nutrients. This review covers in some detail the biochemical, microbiological, and nutritional characteristics of kimchi.     

甘蔗不同基因型贮糖潜力与一些生化性状关系的研究

研究了12个甘蔗基因型贮糖潜力与一些生化性状间的关系。结果表明在甘蔗全生育过程中，叶片蛋白质平均含量、多酚氧化酶和抗坏血酸氧化酶的平均活性表现为高糖基因型＜中糖基因型＜低糖基因型；过氧化物酶和酸性转化酶的平均活性则为中糖基因型＜高糖基因型＜低糖基因型；而中性转化酶活性在各个生育阶段均表现为高糖基因型＞中糖基因型＞低糖基因型。在伸长初期和成熟期，中性转化酶和多酚氧化酶活性分别与蔗茎蔗糖分呈显著和极显著的正相关和负相关关系。通径分析表明在伸长初期，中性转化酶对蔗糖分的直接作用最大，多酚氧化酶的最小。