Plant Foods for Human Nutrition 59: 67–72, 2004.  C 2004 Springer Science+Business Media, Inc. 67 Inﬂuence of Storage Environment, Surface Coating, and Individual Shrink Wrapping on Quality Assurance of Guava (Psidium guajava) Fruits R.K. PAL, ∗ M.S. AHMAD, S.K. ROY & MANOJ SINGH Division of Post Harvest Technology (Horticulture Building), Indian Agricultural Research Institute, New Delhi-110012, India ( ∗ author for correspondence; e-mail: rkpal@iari.res.in; rkrishnapal@yahoo.co.in) Abstract. Guava (Psidium guajava) fruits of cv. L-49 with individual shrink wrapping using 9 μ LLDPE ﬁlm could be successfully stored up to 12 days at ambient and 18 days in evaporative cool chamber with negligi- ble loss in vitamin C content. The untreated fruits lose 25–30% of ascorbic acid within 1 week after harvest. Delay in senescence and metabolic ac- tivities as supported by less changes in soluble solids, sugars, acidity, respiration, and ethylene evaluation rate was also observed in individual shrink wrapped fruits in cool chamber. The spoilage of fruits by Fusarium rots was signiﬁcantly less in cool chamber in individually shrink wrapped fruits followed by Sta-fresh treatment. Sta-fresh was more effective in cool chamber than ambient. Individually stored wrapped fruits scored a better value of sensory score than Sta-fresh under both the storage condition. Key words: Cool chamber, Guava, Individual shrink wrapping, Sta-fresh, Surface coating, Vitamin-C Introduction Guava (Psidium guajava) is an important subtropical fruit grown widely in tropical and subtropical regions of the world including India. It is highly palatable and is one of the choicest fruits having a rich source of vitamin C (260 mg/100 gm pulp). The fruit is highly perishable and loss of vitamin C after harvest takes place very fast which reduces its nutritive value unless appropriate postharvest measures are taken. Use of carbohydrate and lipid based edible waxes for skin coating and individual shrink wrap- ping (ISW) are some of the recent approaches proved to be effective in preventing changes during storage [1]. Such coatings/wrapping can be effective in maintaining quality under ordinary storage conditions [2]. These waxes form a thin ﬁlm around each fruit/vegetable, which acts as semiper- meable membrane to regulate the diffusion of O 2 and CO 2 into and out of the fruit as well as prevent loss of moisture. ISW has also been reported very effective in maintaining quality of fruits/vegetables [3]. High moisture loss from the fruits is the primary factor in deterioration of postharvest quality in tropical and subtropical regions due to high wa- ter vapour deﬁcit. Low cost evaporative cool chambers de- veloped at the Indian Agricultural Research Institute, New Delhi maintains high RH and relatively low temperature are useful for orderly marketing and quality assurance of fresh fruits, vegetables, and ﬂowers for short-term holding [4]. Protocols for extending the marketability of various fruits and vegetables using this on-farm cool chamber have been developed. Loss of moisture from fresh fruits and veg- etables coupled with loss of nutritional components are of signiﬁcant importance towards nutritional security of the harvested produce. Therefore, the experiment was laid out with the objective to study the inﬂuence of surface coating, ISW, and cool chamber storage on the nutritional quality components and organoleptic acceptability of guava. Materials and Methods Fruits were harvested from 10-years-old guava plantation of cultivar L-49 from the experimental orchard of Indian Agricultural Research Institute, New Delhi during the year 2000–2001. Fruits were harvested manually as per the stan- dard maturity indices and were immediately brought to the postharvest laboratory within 2–3 hours of harvest. Man- ual sorting of fruits was done on the basis of size, freedom from diseases and mechanical injuries. Only uniform sized mature fruits with excellent organoleptic acceptability were selected for experimental purpose. Fruits were ﬁrst washed with potable water and dried under a fan. Sta-fresh-960 (SF) is an edible wax ob- tained from FMC, International, UK was used as a sur- face coating material. The major constituents of Sta-fresh 960 include carnuba wax, morpholine, and ammonium hy- droxide, and it is an acceptable surface coating material to be applied on fresh fruits and vegetables as per Food and Drug Administration, USA. The effective concentra- tion of 33% aqueous solution for guava fruits was decided on the basis of preliminary pilot trial. Rolling of fruits over a 5 mm sponge soaked with the coating solution resulted in uniform application of this coating. The fruits were dried under a fan. ISW with 9 μ Linear Low Density Polyethy- lene ﬁlm (LLDPE cling ﬁlm, manufactured locally in India) was done for another group of fruits. The untreated fruits were kept as control. Both the control and the treated fruits were kept at ambient condition (13.5–20.5 ◦ C and 55–80% RH) and in cool chamber (8–12 ◦ C and 88–90% RH). The treatments were replicated six times comprising ten fruits per replication. Periodical observations on various parameters were recorded as per the procedure mentioned below.