State Of Ripeness Research Articles

Improving olive oil quality using CO 2 evolved from olive pastes during processing

The effect of blanketing with CO2, naturally evolved during malaxation of olive pastes, on the quality of virgin olive oil was investigated at lab-scale. The O2 depletion was monitored along with CO2 emission to confirm the previously hypothesized accelerated respiration. Malaxation experiments were conducted for 180 min both in sealed (SC) and in the traditional open-to-air conditions to ascertain whether the oil quality was affected by O2 concentration as afforded by CO2 blanketing. The quality of olive oils obtained at different time intervals was monitored by total acidity, peroxide value (PV), specific extinction coefficients K232 and K270, total chlorophyll and total hydrophilic phenols, and HPLC hydrophilic phenols profile. A rapid decrease in oxygen concentration and a simultaneous increase in CO2 concentration were recorded, confirming the accelerated respiration. The oil produced in SC showed a lower PV and K232 coefficient and a higher chlorophyll (10–17 mg/kg) and hydrophilic phenols (110 mg/kg) concentration. No differences in total acidity and K270 coefficient were observed. The hydrophilic phenols profile indicated that, at least for the Frantoio cultivar and an advanced ripeness state, the maximal extraction is generally achieved already after 20 min. Most of the individual hydrophilic phenols have higher concentrations (up to 50%) in SC.

Evaluation of an electronic nose to assess fruit ripeness

The main goal of our study was to see whether an artificial olfactory system can be used as a nondestructive instrument to measure fruit maturity. In order to make an objective comparison, samples measured with our electronic nose prototype were later characterized using fruit quality techniques. The cultivars chosen for the study were peaches, nectarines, apples, and pears. With peaches and nectarines, a PCA analysis on the electronic nose measurements helped to guess optimal harvest dates that were in good agreement with the ones obtained with fruit quality techniques. A good correlation between sensor signals and some fruit quality indicators was also found. With pears, the study addressed the possibility of classifying samples regarding their ripeness state after different cold storage and shelf-life periods. A PCA analysis showed good separation between samples measured after a shelf-life period of seven days and samples with four or less days. Finally, the electronic nose monitored the shelf-life ripening of apples. A good correlation between electronic nose signals and firmness, starch index, and acidity parameters was found. These results prove that electronic noses have the potential of becoming a reliable instrument to assess fruit ripeness.

Influence of Maturity at Processing on Quality Attributes of Fresh‐cut Conference Pears

ABSTRACT: Influence of ripeness state of Conference pears on the respiration and quality changes of the minimally processed fruit was studied. The fruits processed at partially ripe maturity were the most suitable to obtain fresh‐cut products. Slightly under‐ripe pears exhibited less browning and firmness degradation. Treatments consisting of dips in 10 g/L ascorbic acid and 5 g/L calcium chloride and packaging in 15 cm‐2× m‐2× 24 day‐1× bar‐1 preserved the initial appearance of pear cubes for at least 14 d. Because of a significant inhibition of ethylene production, 0 kPa O2 initial atmosphere was effective in preventing quality changes. Presence of ethanol, as a result of fermentative anaerobic processes, increased with ripeness, especially beyond the 1st 21 d of storage at 4 °C. On the contrary, acetaldehyde was less affected than ethanol by processing and storage conditions.

Volatile composition of coffee berries at different stages of ripeness and their possible attraction to the coffee berry borer Hypothenemus hampei (Coleoptera: Curculionidae).

The analysis of volatile emissions of coffee berries in different physiological states of ripeness was performed using dynamic headspace and gas chromatography/mass spectrometry analysis for Coffea arabica, var. Colombia. The composition of the volatiles emitted by coffee berries is dominated by very high levels of alcohols, mainly ethanol, in all stages of ripeness in comparison with other compounds. Overripe coffee berries have high volatile emissions and show a composition dominated mainly by esters followed by alcohols, ketones, and aldehydes. The lowest level compounds were monoterpenes. 2-Methyl furan was detected in various ripening stages; this compound has not been previously reported as a coffee berry volatile. The presence of ethanol and other alcohols in the volatile composition might explain the effectiveness of using traps with mixed alcohols for detection and capture of coffee berry borers.

Analysis and identification of several apple varieties using ISFETs sensors

There are a number of variables that are useful to determine the optimal moment for the fruit collection such as starch content, sugar content, acidity and firmness. Other variables, including calcium and potassium concentrations, may establish better the state of ripeness of fruit and can help to optimise the collection process as well as augmenting the nutritional value of fruits. At present, these novel parameters cannot be used for the control of fruit collection due to the slow standard methods required. The need for in situ and in real-time ion measurements calls for fast response sensors and simpler and portable instrumentation. Solid-state sensors respond to these requirements. This work describes the application of ISFET sensors to analyse calcium, potassium and nitrates in several apple varieties, both in juice and in situ fruit. Results show that the analysis of potassium, calcium and nitrate permits to distinguish among apple varieties and can also be used to determine correctly the concentrations of these ions.

A histological study of reproduction in the serpulids Pomatoceros triqueter and Pomatoceros lamarckii (Annelida: Polychaeta)

The reproductive cycles of the serpulid polychaetes Pomatoceros lamarckii (Quatrefages, 1865, as Vermilia) and P. triqueter (Linnaeus, 1767, as Serpula triquetra) were studied by histological examination during 1999 and 2000 at Bantry Bay, south-west Ireland. Gametogenesis, sex ratios and hermaphroditism were also investigated. The male/female ratio in P. lamarckii was approximately equal, but in P. triqueter it deviated significantly in favour of females. There was no significant variation in the sex ratios throughout the year in either species. Results confirm that the species are protandric hermaphrodites. In P. lamarckii, but not in P. triqueter, sexual dimorphism was exhibited in body size, the females being larger than the males of the same species. In both species, the proportion of females increased with increasing body size. Simultaneous hermaphroditism was recorded in P. lamarckii, but not in P. triqueter. There was no clearly defined annual gametogenic cycle in either species. Both species appear to have an extended reproductive season, with numerous small-scale peaks in reproductive maturity that can vary annually. Spawning was broadly synchronous between sexes. Visual observation alone (i.e. without histology) was insufficient to accurately assess reproductive condition in individuals not in, or close to, a ripe state.

Storage of fresh figs in low oxygen atmosphere

SummaryFresh ‘Mavra Markopoulou’ fig fruits, harvested close to a fully ripe state in October, were stored at 1C in either air or 2% O2 (balance N2) for 29.d. During storage in air the rates of O2 uptake and ethylene production declined substantially and fruit weight loss increased up to 2.1%. Storage in 2% O2 resulted in further reduction of O2 uptake and ethylene production rates. The effects of storage conditions on ripening indices at 20C in air were also investigated. Fruit stored in air showed decreased firmness, ethylene production rate and flesh colour lightness, but no significant or consistent changes in respiratory quotient, O2 uptake and CO2 production rates, soluble solids content, titratable acidity and other colour changes in peel or flesh were observed. In contrast, storage in 2% O2 resulted in decreased respiratory quotient (although values remained above 1), O2 uptake and CO2 production rates and prevented fruit softening, loss of green peel colour and decrease in flesh lightness during post-storage at 20C. All fruit were stored successfully under the above conditions, but 2% O2 is recommended for better firmness retention during storage for longer than 8.d.

Correlation between electronic nose signals and fruit quality indicators on shelf-life measurements with pinklady apples

In this work, an electronic nose is used to assess the ripeness state of pinklady apples through their shelf-life. In order to evaluate the electronic nose performance, fruit quality indicators are also obtained to compare results from both techniques. Pinklady apples were harvested at their optimal date so that electronic nose measurements and fruit quality measurements could be performed on the fruit samples during their ripening process. A PCA analysis, a well-known linear classification technique, does not show any clustering behaviour that might be attributed to ripening. On the other hand, Fuzzy art, an unsupervised neural network classification algorithm, shows a tendency to classify measurements regarding to their shelf-life period. Finally, electronic nose signals are correlated with classical fruit quality parameters such as firmness, starch index and acidity. Good correlation coefficients are obtained, a clear indication that electronic nose signals are related to the ripening process of apples.

Change in the natural ratio between chlorophylls and carotenoids in olive fruit during processing for virgin olive oil

AbstractDifferent varieties of olives from different sources, harvested in a similar ripeness state, have been characterized by their chlorophyll and carotenoid pigment profile and content. Pigment richness is inherent to the variety and enables great differences or similarities to be established between them. In all the fruits, ripening involves pigment loss, with the disappearance of chlorophylls always being slightly greater than that of carotenoids. However, independently of variety and the different pitment content of the fruits, the ratio between chlorophylls and carotenoids tends to remain more or less constant, within a range of 2.5 to 3.7 mg total chlorophyll/mg total carotenoid. Pigment loss caused by the extraction process is more marked for the chlorophyll fraction than for the carotenoids, changing the ratio in the oil to around one unit, whatever the variety of soruce fruit.

Fruit ripeness monitoring using an Electronic Nose

In this work, the use of an Electronic Nose for non-destructively monitoring the fruit ripening process is presented. Based on a tin oxide chemical sensor array and neural network-based pattern recognition techniques, the olfactory system designed is able to classify fruit samples into three different states of ripeness (green, ripe and overripe) with very good accuracy. Measures done with peaches and pears show a success rate above 92%, while a slightly worse accuracy is reached with apples. An additional feature of the system is its ability to accurately predict the number of days the fruit has been in storage since harvest. Measures done with peaches show a maximum error of 1 day.

Note. The ripening of Prunus persica fruits with a dominant flat allele Nota. Maduración de frutos de Prunus persica con un alelo dominante de la forma achatada

The changes of peaches ( Prunus persica, L.) with a predominant flat allele were studied during their ripening on the tree. Physicochemical and physiological parameters were analyzed between days 101 and 121 after fruit set. During this period, the weight ranged from 65 g (corresponding to fruit growth stage III) up to a stabilized weight of 90 g when the fruit was ripe. The color changes that characterized fruit ripening began to appear on day 112 after fruit set, with a decrease in the hue angle value both in the skin and pulp. Firmness diminished along the experience from 6.75 to 3.03 Monet units in ripe state. Ripened fruit was also characterized by a soluble solid content of 13.43 °Brix and 0.178% malic acid as titratable acidity. The ripeness index increased throughout maturation from 25.41 at the outset to 44.42 on day 112 after fruit set, and 75.45 at the end of the experiment. The fruit showed a clear climacteric behavior with increased ethylene production and respiration rate. The onset in both processes started on day 112 after fruit set, reached a maximum on day 116, and decreased thereafter. Changes in the content of free and conjugated 1-aminocyclopropane-1-carboxy lic acid (ACC) were coincident with those of ethylene evolution throughout ripening. In regard to polyamine levels, putrescine showed a peak slightly later than that of ethylene and ACC.

Carotenoid content of the varieties Jaranda and Jariza (Capsicumannuum L.) and response during the industrial slow drying and grinding steps in paprika processing.

Fruits of the pepper varieties Jaranda and Jariza (Capsicum annuum L. ) ripen as a group, enabling a single harvesting, showed a uniform carotenoid content that is high enough (7.9 g/kg) for the production of paprika. The drying system at mild temperature showed that fruits with moisture content of 85-88% generated a dry product with carotenoid content equal to or higher than the initial one. Those high moisture levels allowed the fruits to have a longer period of metabolic activity, increasing the yellow fraction, the red fraction, or both as a function of what biosynthetic process was predominant. This fact indicates under-ripeness of the fruits in the drying step. The results obtained allow us to establish that both varieties, Jaranda and Jariza, fit the dehydration process employed, yielding a dry fruit with carotenoid concentration similar to that the initial one. During the grinding step of the dry fruit, the heat generated by the hammers of the mill caused degradation of the yellow fraction, while the red fraction is maintained. The ripeness state of the harvested fruits and the appropriateness or severity of the processing steps are indicated by the ratio of red to yellow (R/Y) and/or red to total (R/T) pigments, since fluctuations in both fractions and in total pigments are reflected in and monitored by these parameters.

FOSTERING RIPENESS IN SEEMINGLY INTRACTABLE CONFLICT: AN EXPERIMENTAL STUDY

Disputant “ripeness” is a state and a process of critical importance to the resolution of seemingly intractable conflict. Fostering ripeness is often a primary goal of those who attempt to intervene. This study presents a typology of interventions for promoting ripeness in highly escalated, protracted conflicts, and investigates the distinct effects of four different types of intervention strategies on the commitment of disputants to make peace. The model defines a state of ripeness at the individual psychological level as a high level of commitment by a party to change the direction of the normative escalatory processes of the relations towards deescalation. Lewin's “drive” and “resistance” change‐force strategies are combined with “process” and “outcome” oriented interventions to yield the four strategies. Results indicated that process‐oriented interventions targeted at removing resistance obstacles to peace were more effective at fostering ripeness than outcome‐oriented interventions aimed at driving constructive change. The implications of the findings are discussed.

Application of headspace solid-phase microextraction to volatile flavour profile development during storage and ripening of kiwifruit

Kiwifruit volatile flavour compounds were evaluated with headspace solid-phase microextraction (SPME) as a sample concentration technique. Gas chromatography–mass spectrometry (GC–MS) was used for qualitative and semi-quantitative analysis after SPME. Components such as heptanal, ethyl hex-3-enoate, 6-methylhept-5-en-2-one, acetic acid, c/t-2-nonenal (mixture) and c/t-2-decenal (mixture), which were previously found only in kiwifruit juice, were detected by headspace SPME–GC–MS. Other compounds (pent-4-enal, t,t-nona-2,4-dienal, 2-nonanone, ethyl octanoate, butyrolactone and 2-propenyl butanoate), which had not been found previously, were identified. Flavour volatiles of kiwifruit were very sensitive to storage time and state of ripeness.

Neural network based electronic nose for apple ripeness determination

It is possible to non-destructively determine apple ripeness using a simple electronic nose. The instrument employs tin oxide resistive gas sensors and neural networks (fuzzy ARTMAP, LVQ and MLP) to classify the samples into three states of ripeness with 100% accuracy. Fuzzy ARTMAP was found to be the best classifier in the presence of simulated Gaussian noise.

Non-destructive banana ripeness determination using a neural network-basedelectronic nose

An electronic nose based system, which employs an array of inexpensive commercial tin-oxide odour sensors, has been used to analyse the state of ripeness of bananas. Readings were taken from the headspace of three sets of bananas during ripening over a period of 8-14 days. A principal-components analysis and investigatory techniques were used to define seven distinct regions in multisensor space according to the state of ripeness of the bananas, predicted from a classification of banana-skin colours. Then three supervised classifiers, namely Fuzzy ARTMAP, LVQ and MLP, were used to classify the samples into the observed seven states of ripeness. It was found that the Fuzzy ARTMAP and LVQ classifiers outperformed the MLP classifier, with accuracies of 90.3% and 92%, respectively, compared with 83.4%. Furthermore, these methods were able to predict accurately the state of ripeness of unknown sets of bananas with almost the same accuracy, i.e. 90%. Finally, it is shown that the Fuzzy ARTMAP classifier, unlike LVQ and MLP, is able to perform efficient on-line learning in this application without forgetting previously learnt knowledge. All of these characteristics make the Fuzzy-ARTMAP-based electronic nose a very attractive instrument with which to determine non-destructively the state of ripeness of fruit.

Compositional and Isotopic Studies of Fruit Flavours. Part I. The Banana Aroma

The determination of the molecular composition and the 13 C content of some of the main constituents of the banana aroma by GC, GC-MS and 13 C GC-C-IRMS was carried out on fruits, commercial nectars and industrial aromas. From the consideration of primary (i.e. isobutyl and isoamyl acetate) and secondary (i.e. pentan-2-one, isoamyl butyrate) metabolites, mass and isotopic balances can be defined which are good indicators of the nature of the fruit studied. Bananas from different geographical origins (Ivory Coast, Martinique, Central America) and harvested in different states of ripeness have characteristic fractionation patterns. It is also shown that commercial nectars have molecular and isotopic compositions similar to those of the volatile fraction of very mature fruits. Industrial aromas have particularly typical 13 C composition, depending on whether they are natural or synthetic.

Influence of freezing rate and the ripeness state of fresh courgette on the quality of freeze-dried products and freeze-drying time

Industrial freeze-drying of courgette sometimes leads to the alteration of both the appearance and the texture of the freeze-dried product and to varying freeze drying times. Two factors may be involved in these phenomena: the freezing rate and the ripeness state of the raw material. In this study, we show that the freezing rate has no influence on the final quality of the product nor on the dehydration time. On the other hand, the degree of ripeness seems to be of prime importance and can be easily estimated by colorimetric measurements on the fresh vegetable skin or by calorimetric measurement of the glass transition temperature. We also propose a colorimetric criterion for selecting courgettes before processing and predicting the luminance of the freeze-dried product.

Relative risks of fungal rot for temperate ericaceous fruits: effects of seasonal variation on selection for chemical defense

To quantify factors influencing the risk of fungal rot for vertebrate-dispersed fruits and to refine predictions concerning antifungal defense patterns, we examined physical, chemical, and phenological characteristics of ericaceous plants in New Jersey. In the field, three summer-ripening species had shorter persistence in the ripe state, shorter total retention times, and lower fungal resistance than three fall-ripening species. Summer fruits also had higher pulp carbohydrate content, lower fiber content, and (or) lower seed/pulp ratios. Whereas fungal colonization rates were somewhat lower during the ripening periods of summer species, fungal growth rates were higher owing to higher summer temperatures. In vitro fungal growth tests indicated only small effects of pulp nutrient content on fungal growth. We suggest that seasonal and chemical nutrient factors influencing risk of fungal rot for our study species are of minor significance relative to the degree to which these factors affect fruit removal by dispersers. We predict that owing to selection for high palatability, summer species should exhibit antifungal defenses with little or no antifrugivore effects (microbe-specific defenses). We also predict that because of consistently high removal rates (lower apparency), summer fruits should exhibit antifungal defenses less effective than those of fall species. Key words: antifungal defense, coadaptation, fruit rot, fruit nutrients, secondary chemistry, seed dispersal.

6. Domestication rates in wild-type wheats and barley under primitive cultivation

Man's first cereal crops were sown from seed gathered from wild stands, and it was in the course of cultivation that domestication occurred. This paper prcsents thr preliminary rrsults of an experimcntal approach to the measurement of domestication rate in crops of wild-type einkorn wheat exposed to primitive systems of husbandry. The results indicate that in wild-type crops of einkorn, emmer and barley (a) domestication will have occurred only if they were harvested in a partially ripe (or near-ripe) state using specific harvesting methods; (b) exposure to shifting cultivation may also have been required in somr cases; and (c) given these requirements, the crops could have become completely domcsticated within two centuries, and maybe in as little as 20–30 years without any form of conscious selection. This paper (1) considers the possible length of delays in the start of domestication due to early crops of wild-type cereals lacking domestic-type mutants; (2) examines the combination of primitive husbandry practices that would have been necessary for any selective advantage to have been unconsciously conferred on these mutants; (3) considers the state of ripeness (at harvest) necessary for crops to be able to respond to these selective prcssures; (4) outlines field measurements of the selective intensities (selection coefficients) which arise when analogous husbandry practices are applied experimentally to living wild-type crops; (5) summarizes the essential features of a mathematical model which incorporatcs these measurements of selection coefficients and other key variables, and which describes the rate of increasc in domestic-type mutants that would have occurred in early populations of wild-type cereals under specific combinations of primitive husbandry practices; (6) considers why very early cultivators should have used that combination of husbandry methods which, we suggest, unconsciously brought about the domestication of wild wheats and barley; and (7) concludes by considering whether these events arc likely to have left recognizable traces in archaeological remains.