Investigatory: Fruit and Shelf Life

Background of the Study The devastating economic condition of the world today is caused mainly by the decreased resources and products. Hunger is one of the problems the Philippines is currently facing according to the different surveys. Exasperating the scenario is the short shelf lives of the products produced. But nature has provided humanity with very beautiful and useful plants. It is the duty of the young generation to search on how to maximize these gifts of nature so as to address the numerous problems they are faced with. Food spoilage contributes to the loss in the income of many farmers in like manner that it also heightens the prices of their produce. Raw foods naturally contain enzymes that promote degradation and chemical changes which affect flavor and texture.

Thus, preservation techniques are necessary. Sayote also known as chayote is viviparous and has a tendency to sprout under postharvest storage conditions. It contains cytokinins, a chemical composition present in its seeds that prolong the shelf life of certain fruits. Not like other multi-seeded cucurbitaceous fruits like watermelon, pumpkin, cucumber, and melon which are propagated by seeds, sayote is propagated by planting the fruit. The seed enclosed within the fleshy fruit has no dormant period, undergoes no dehydration, and sprouts readily at 20º-35 ºC temperatures.The readiness of chayote fruit to sprout under postharvest storage conditions poses a major impediment to its long-term preservation, marketing, and utilization.

The locals are fairly informed with the utilization of the plant from tip to tip hence the researchers thought of finding ways in exploiting the said plant in a new approach; using it for food preservation. The researchers decided to use the sayote seeds as a substitute to the different kinds of preservatives, for they observed that it was just thrown away.This will promote an innovative healthy and acceptable way of food preservation especially to fruits.

Hypotheses

Based on the statement of the problem, the following hypothesis was considered in this study: 1. The sayote seeds is effective as a prolonging agent to the shelf life of selected fruits. 2. The shelf lives of the fruits in the different treatments are comparable. 3. The extent of maceration of the fruits in the different treatments is comparable. 4. There are significant effects of the different treatments in terms of taste and odor of the fruits.

Significance of the Study

This study hopes to help farmers increase the shelf life of fruits, thereby increasing their income. If this study will yield positive results, then this will be a healthy substitute to the commercially availed chemical preservatives. Fruits which are not in season will be available in the market. As a result, the research will give an explicit impact in the country’s agriculture and economic state. This study may also encourage other people to make solutions to the problems their country or society is facing. Most importantly, this can also lead to other discoveries and creation of new products out of sayote seeds.

Scope and Limitations

This study was conducted during the months of February to July 2012 at Ilocos Sur National High School, Vigan City. The actual experimentation was done at Barangay Pagpartian, Vigan City. The sayote seeds were utilized as prolongoning agent to the shelf life of selected fruits namely tomatoes, lanzones, longgan and kiwi fruits.The shelf life of the fruits was determined by counting the days before the fruits showed indications of maceration. Sensory evaluation test was employed to determine the extent of maceration of the fruits after one weekof application and the acceptability of the prolonging agent to the shelf life of fruits in terms of taste and odor. The following statistical tools were used in the analysis of data gathered: frequency, percentage, mean and anova.

To further understand the study, the researchers pointed relevant literatures and studies associated to the present study which serve as the foundation, backbone and strength in the realization of positive results and outcomes of this worthy endeavor. Sayote, also known chayoteis viviparous and has a tendency to sprout under postharvest storage conditions. Ogawa demonstrated the presence of gibberellin-like substances in chayote seed extracts and found a high level of growth-promoting activity from developing seed about 5-weeks from anthesis. The peak of GA-like substances preceded the growth of the fruit and seed which suggested that these substances are involved in the development of the organs.

Later, Aung and Flickshowed exogenous application of gibberellin A3 and A4/7 in lanolin on the stigmatic surfaces of chayote flowers stimulated the growth of the ovarian tissues, but inhibited embryo/seed development which resulted in parthenocarpic fruit. Using gas chromatography and mass spectrometry, Lorenzi and Ceccarellifound gibberellin A4 and A7 were major growth substances in the seed and flesh of chayote fruit during different stages of development. Additionally, a cell-free preparation of chayote endosperm and cotyledonary tissues possessed the necessary biochemical factors to convert 14C-mevalonic acid to entkaurene and gibberellins. Subsequently, Albone et al. identified 20 gibberellins in chayote embryo, endosperm and seedcoat, and showed gibberellin A1, A3,A4, and A7 to be major gibberellins in chayote fruit.

The observations support the view that gibberellins are important in the development of chayote seed and fruit.Therefore, it was of interest to determine the effect of gibberellins and gibberellin-antagonists on chayote sprout development under postharvest conditions. Chemical regulators sources and preparation. Gibberellin A3 (Sigma Chemical Company, St. Louis, Missouri, USA), gibberellin A4/7(Merck, Rahway, New Jersey, USA), gibberellin A1(Kyowa Hakko Kogyo Company, Ltd, Japan; sample courtesy of Dr. Y. Sumiki), abscisic acid (Sigma Chemical Company, Missouri, USA), Tetcyclacis (BASF, 96%, Aktiengesellschaft, Ludwigshafen, Germany) and prohexadione (BASF, 10% powder, Research Triangle Park, North Carolina, USA; sample courtesy of Dr. Reid Evans) were used.

The chemical regulants at the specified concentrations were initially dissolved in 50 µl of alcohol and diluted to the desired volume with distilled water. Tween-80 (polyoxyethylenesor-bitanmonoleate) was added as a surfactant. The final reagent solution contained 1% alcohol (v/v) and 0.05% Tween-80 (v/v). Method of chemical regulators application. Gibberellins (GAs, 1mM), abscisic acid (AbA; 50 µM), tetcyclacis (TC; 1mM), and prohexadione (1mM) were injected with a Hamilton syringe via a punched fruit cavity of 5 mm diameter and 25 mm depth adjacent to the embryonic shoot of the seed.Solution volume of 400 µl of each regulant was injected per fruit cavity which was than covered with a piece of adhesive tape.Each treatment consisted of 4 replicates with 3 fruits per replicate.The treated fruits were maintained in environmental rooms at 25 ºC conducive to sprout development or at 15 ºC which retards sprouting. Data analysis. Sprout length and emergence were used to gauge development in response to the treatments.

The data obtained were analysed using the analysis of variance procedure and the least significant difference at probability level of 5% or 1% was used for comparing treatment means.Percentage data were transformed using arc sine √% before analysis of variance computation. Linear regression of sprout length and development time was calculated to depict prohexadione sprout retarding effect. The phenomenon of vivipary in chayote, a herbaceous perennial plant, finds few equals in the plant kingdom. The growth habit of chayote can be contrasted with other seed-bearing crop plants where seed germination occurs only after undergoing a requisite period of dehydration, whereas the enclosed seed of chayote within the fleshy pericarp maintains a high water content of 80-90% on a fresh wt. basis continues to grow and mature throughout ontogeny. Even in plants that do not undergo a period of dehydration for germination, their seeds are normally detached from the fruit for planting. In contrast, chayote seed remains intact within the fleshy fruit and the entire structure is used for propagation.

In commercial practice, chayote fruit is harvested immature for sale and consumption.Thus, the endogenous seed continues to grow under postharvest conditions utilizing the stored water and nutrients existing at the time of severance from the mother plant. We have observed that a sprouted chayote fruit grew a 1-2 m long shoot during a 6-8 week period using primarily its stored water and nutrients, and with only its embryonic roots immersed in distilled water at 25 ºC under dim light. Under these conditions, the developing shoot completely resorbed and utilized the entire fruit content leaving only the epicarpic shell. Chayote seed grows continuously without dormancy or dehydration within the fleshy fruit, and it appears that exogenous postharvest application of hormonal compounds must in effect influence or modulate on-going metabolic/cellular processes rather than on the processes initiating sprouting.

Furthermore, the exogenous substances could interact with endogenous hormonal substances which have a primary/direct role(s) in the initiation of sprout growth and its development. The biological activity of endogenous GA-like substances in chayote fruit tissues was shown by Ogawa.Subsequently, the chemical identity of the GAs in the seed and fruit tissues of chayote was demonstrated unequivocally by GC/MS. However, the specific function(s) of GAs in chayote growth and development is still lacking. Ceccarelli and Lorenzi showed GA conjugates and 16, 17-dihydro-16-hydroxy-GA15 alcohol glucoside of cotyledonary tissues promoted shoot growth of plantlets grown under short photoperiod of 8-h in a greenhouse at 15º-25ºC. Also, a foliar spray application of GA4/7 restored shoot growth of the decotylized plantlets.

From these observations, they inferred that GA-conjugates or the products of hydrolysis of the cotyledons were involved in shoot growth.Given the fact that both cytokininsand indole-3-acetic acid are also present in chayote seed tissues, it is not unreasonable to suggest that GAs acting synergistically or interactively with these compounds probably are involved in shoot growth. Seeds of Sechium edule, a viviparous species, contain highlevels of gibberellins and cytokinins throughout seed growthand development. Endogenous levels of ABA in thesame seeds have been also investigated, and absence of hormone accumulation in coincidence with the maximal seedgrowth, as observed in other species, has been noticed.

Report here on the quantification of ABA in integumentsand nucellus of pollinated and unpollinated Sechiumovules. The very small amount of tissues available for each stage of ovule development has raised the need for a very sensitive and accurate methodology. This was accomplished by using a recently developed solid-phase RIA' based on amonoclonal antibody against free (S)-ABA. This monoclonal antibody has affinity and specificity high enough to allow the precise quantitation of very low levels of ABA inaqueous plant crude extracts. Salt tolerance was increased in seeds subjected to 25 ppm kinetin and 1% prostart (2 h) as indicated by shoot and root length, shoot fresh and dry weight. Better performance of seedlings raised from seeds primed with kinetin might be due to increased invertase, α- amylase and starch synthetase in wheat (Sekhon and Singh, 1994).

These results are also in accordance, to some extent, with the studies of Patel and Saxena (1994) who reported that fresh and dry weight was increased in seedlings raised from seeds treated with kinetin and GA3 as compared to seeds treated with NAA and Ethrel. These results further relate with the studies of Angrishet al. (2001) who reported that amelioration of salinity was due to enhanced N status and nitrate reductase activity through pre-sowing wheat seeds with plant growth regulators like cytokinins.

Cytokinin biosynthesis in endosperm of Sechium edule Sw.

Alberto Piaggesi, Piero Picciarelli, Nello Ceccarelli, Roberto Lorenzi Endosperm of Sechium edule seed was incubated with [U-14C] adenine and [13C]mevalonic acid for 17 h. Following incubation, cytokinins were extracted and purified by HPLC. Using GC-MS, incorporation of [13C]MVA into isopentenyladenine and zeatin riboside was demonstrated. This is the first unequivocal demonstration of cytokinin biosynthesis in a normal plant tissue because precursor’s incorporation into cytokinins was demonstrated by MS.

The significance of these results is also discussed in relation to a possible mononucleotide-independent pathway of cytokinin biosynthesis. William Nault (1996) states that wax is a fatty acid substance that is widely used as a protective coating for various surfaces. It resists air, water and chemical change. Many plants have a natural wax coating them from heat and moisture.

Moreover, the researchers undertook the study to find out if the variables earlier cited are significantly related to the effect of sayote seeds as prolonging agent to the shelf life of selected fruits, which can, among other things, be a handy reference for future studies and planners of change especially in food preservation. From the different studies and researchers cited, with their shades and tones primarily about sayote, shelf life and prolonging agent, the present study shaped into its final form and substance.