- Author: Ed Perry
Fruit color is a poor indication of ripeness, because many fruits have fully colored rinds a long time before they can be eaten.
Don't expect citrus fruits to increase in sweetness or ripen more fully once you've picked them, as do peaches and some other fruits. When picked at any stage of maturity, citrus fruit does not change after picking, except that it may decay or slowly dry out.
When you're picking citrus fruit that you plan to store for awhile, be careful not to bruise or break the skin. Fruits that are cut or scratched during harvesting will rot fairly quickly in storage. Citrus fruits with perfectly sound skin are fairly decay proof, and will last in cool, moist storage for several weeks (38 to 48 degrees F, 85 to 95 percent relative humidity). Under dry conditions at room temperature, fruits develop off flavors and shrivel within a week to 10 days.
Ed Perry is the emeritus Environmental Horticultural Advisor for University of California Cooperative Extension (UCCE) in Stanislaus County where he worked for over 30 years.
- Author: Ben Faber
The avocado is an amazing fruit. It grows on a tree and comes to maturity, reaches certain oil content and a stage at which it will ripen, but it does not ripen on the tree. It needs to be removed from the tree before it will soften. If the fruit is removed before it has reached maturity it will not soften, and will remain rubbery and inedible. One of the problems is that the fruit will hang on the tree for an extended period of time and it is hard to know when they are mature. Avocados are not like apricots where you have about 2 weeks to get the fruit off before it falls off. As the fruit stays on the tree in gradually develops more and more oil content and has a richer flavor.
If the fruit stays on the tree too long, the oil can develop and almost rancid flavor, however. So it is good to know when the best, acceptable flavor is. Avocado varieties fall into general seasonal periods when they are mature, such as Fuerte' and ‘Bacon” in winter, ‘Hass' in spring/summer, ‘Lamb-Hass' in summer/fall.
To assess maturity, take an unripe stage cut the fruit in half. Look at the seed coat. If the seed coat (the covering of the seed that separates it from the flesh) is white and thick, it is definitely not ready to pick. If it is whitish brown and getting thinner, then if you are desperate, you can try ripening the fruit and taste. If the seed coat is thin and brown, then usually this will mean that the fruit is ready to pick. If the seed has germinated already in the fruit then normally the fruit is over the hill. Some green skin varieties skin will begin to crack when the fruit are very mature on the tree. This will tell you when you have reached the end of the useful tree life of the fruit.
For ripening, pick the fruit and without any help, the fruit will typically be ripe in 7 to 10 days. If you want to speed things along a bit you can take 3 or 4 avocados and place them in a loosely closed paper bag with 2 – 3 Red or Golden Delicious apples or ripe kiwifruit. The purpose of the apples or kiwifruit is that these fruit produce a natural plant hormone, ethylene that will help stimulate the avocado to produce its own ethylene. Apples and kiwifruit are known to produce lots of ethylene. The Delicious apples are varieties that produce more ethylene than other apple varieties. You can keep them even after they are shriveled and they will be producing ethylene. Don't use a plastic bag unless you keep it opened since the fruit need to breathe during this process. Just keep the fruit on your kitchen counter or in a warm place. 68F is the ideal temperature. Lower and higher temperatures both actually slow the process.
- Author: Stephen J. Vasquez
Harvest season will soon be upon us in the San Joaquin Valley, which means that testing fruit for maturity will become a daily task beginning shortly after veraison. Proper sampling for sugar is important for making decisions on harvesting specific varieties or locations. Often referred to as “soluble solids” or “sugar” testing, fruit maturity evaluation involves sample collection and testing procedures that accurately represent the crop. Testing for sugar content in fruit has become easier as technology has improved. However, improved technology cannot eliminate deficiencies in sample collection or errors caused by poor refractometer care and maintenance.
Calibrating the refractometer is the first step in evaluating sugar content of fruit. It is an easy but often neglected task. Calibration verifies the zero baseline reading, ensuring that subsequent fruit juice sample readings are accurate.Fruit harvest decisions based on inaccurate sugar readings can impact quality, storage durability and sales. Refractometers should be calibrated at the beginning of each use and, depending on how many samples are being measured, periodically throughout the sampling process.
Proper calibration requires a pure water source and testing solutions of known sucrose concentration. Water allows the user to “zero” the refractometer so fruit juices can be correctly measured. A solution with a known sucrose concentration gives the user confidence in the accuracy of the instrument.
Given the delay in maturity throughout the state, grape growers should take the time to properly calibrate their refractometers so correct soluble solids levels can be documented and harvest dates arranged according to cultivar, maturity, block, etc.
Learn more about proper refractometer calibration, use and maintenance here.
- Author: Mary E. Reed
Americans, after years of hearing that fresh produce is valuable for numerous health benefits, have still not significantly increased their consumption. So, why don’t we eat more fruits and vegetables? Researchers believe that the key reason is that the quality of produce is inconsistent – often with poor texture, flavor or aroma. It might look beautiful on the outside, but when you take a bite – Ugh! It just doesn’t match up to its attractive exterior.
Most produce found at the local market is harvested from the field or orchard before it is fully ripe, shipped a long distance, and then the ripening is completed at a regional produce distribution center or at the local market.
“Harvesting produce early reduces losses due to bruises, decay and other defects,” explained Beth Mitcham, SCRI Grant UCD project leader, “but oftentimes the product never reaches its potential, a full ripe flavor or aroma. Fresh produce, especially when harvested near full ripe stage, can be challenging to handle properly.”
The SCRI grant is an ambitious effort to understand what characteristics are critical for consumers to enjoy produce and develop better methods to measure flavor quality, then work with better tasting varietals and improved shipping and handling practices to allow economically viable delivery of truly delicious fruits and vegetables.
Consumer focus groups are being interviewed for their input, trained taste panels are enjoying a variety fresh produce, and experiments with pallet shrouds and other modified atmosphere transportation experiments are underway. Significant information has already been elicited from consumer groups. Through focus groups, the investigators have discovered that aroma and texture are nearly as important as sweetness, and shoppers get really irritated when produce looks good but tastes bad, and this keeps repeat purchases to a minimum.
Produce managers also have a tough time: set up displays of produce, keep it at the right temperature, watch people wandering around squeezing everything to see if their firmness requirements are met, meanwhile damaging the fruit. It’s a tough market for fresh fruit these days, with fewer consumers’ dollars allocated for produce purchases, but with the advances researchers are making through the SCRI project and others, sweet success is on the way.
Note: This topic was featured on a CBS13 (KOVR) News clip dated 7/17/10, see: http://www.cbs13.com/video/?id=76639@kovr.dayport.com