What is Pressure Canning?

Joel MacCharles wrote . . . . . . . . .

Let’s start with a definition:

“Pressure canning is a technique of home food preservation that uses special equipment to process food at a higher temperature than ‘normal’ waterbath canning. It is primarily used to can meat and vegetables without the need for adding high acid (like pickles).”

We use a pressure canner (it’s similar but different from a pressure cooker) to can peas, asparagus, stock, soup and more. The process makes these things shelf-stable so they produce homemade versions of canned vegetables and stocks found in the produce aisle. The homemade version can be a superior product as you can choose the ingredients (including lowering or emitting salt and avoiding preservatives alltogether).

How Does Pressure Canning Work?

Let’s start by discussing how water bath canning works: jars are covered in boiling water and processed for a certain amount of time. Water can only reach 100 degrees Celsius (212 Fahrenheit); the boiling water raises the temperature of the ingredients within the jar to kill bacteria. You use this technique for high-acid foods as they are safe to process at these temperatures.

Pressure canning uses less water (the jars aren’t covered) as it traps steam inside a pressurized container to raise temperatures beyond 240 degrees Fahrenheit. This allows us to preserve food that otherwise would require acid to be added to it.

What Are the Advantages of Pressure Canning?

There are several advantages to pressure canning, including:

  • It maintains the flavor of the ingredients (peas and asparagus taste almost as fresh as they were canned).
  • It uses less water and less energy (debatable) than water bath canning.
  • It allows you to store items on the shelf without needing the space, budget or energy for a freezer or cold cellar.
  • As mentioned above, you can control the ingredients that are added to your preserved foods.

What Are the Disadvantages of Pressure Canning?

  • It requires specialized equipment that can be expensive (most canners are around $100) that can also be difficult to store. I use my pressure canner (without the lid) as my pot for waterbath preserving so it sees lots of use. We’ll share guidelines on what to look for when buying a canner later this week.
  • It can be intimidating. The equipment is more technical than most preserving equipment and there’s less people who do it which makes it a little more difficult to learn/ wrap your head around. Once you do it a few times you’ll find it’s no more difficult that ‘normal’ canning. If you’ve never used a waterbath (i.e. to preserve jam, pickles or tomato sauce), you may want to start there.
  • The texture changes. Vegetables will be softer as they are fully cooked (although every preserving method changes the texture of the original product in some way).
  • Canners take maintenance (for example, a dial-gauge canner should be checked yearly for accuracy)

What’s the Basic Process?

The following is a general overview:

  1. A few quarts of water is added to the canner and turned on high. You add enough water to ensure that it won’t run out when boiling during processing but not enough to cover the jars.
  2. Vegetables/ product is heated and added to clean mason jars.
  3. Rims of the jars are wiped clean, lids attached and placed in the canner (generally before boiling as you’ll see in the resource article below).
  4. The lid is secured on the canner and it’s ‘brought up to pressure’ meaning that the water is brought to a full boil and the pressure accumulates within the pot until a certain temperature is met. Canners let you know that temperature has happened by by a dial or a weight that wiggles in place.
  5. Food is processed for a specific time (which has to be adjusted if you’re at extreme altitude).
  6. Heat is turned off and the canner is allowed to cool before removing the lid and the jars.
  7. Jars are cooled for 24 hours before being placed on a shelf or in a larder.

Source: Well Preserved


Read also at National Center for Home Food Preservation:

Preserving Food: Using Pressure Canners . . . . .

Vegetarian Korean Hearty Soup – Doenjang Chigae

Ingredients

1/2 oz dried shiitake mushrooms (2-4, depending on size)
1 vegetarian yuksu or dashi bag
1 tbsp sesame oil
1-3/4 oz onion
1 large garlic clove, peeled
4-1/2 oz medium tofu
1/2 zucchini, about 5 oz
1-3/4 oz shimeji mushrooms
1-3/4 oz enoki mushrooms
1 red or green banana chili
1/2 tsp gochugaru (Korean chili flakes), or to taste
1-3/4 oz doenjang
1 egg
1 spring onion

Method

  1. Rinse the dried shiitake mushrooms in cool water, then put them in a bowl and add 1-1/4 cup warm water. Leave to soak at room temperature for about two hours, until soft. Squeeze the water out of the mushrooms, reserving the soaking liquid. Remove and set aside the mushroom stems and thinly slice the caps.
  2. Pour the soaking liquid into a small saucepan, add the reserved mushroom stems, then bring to the boil over a medium flame. Turn off the heat, add the yuksu or dashi bag and leave to infuse while preparing the other ingredients.
  3. Mince the onion and slice the garlic. Cut the tofu into bite-size cubes. Quarter the zucchini lengthwise, then slice it thinly. Trim off the woody lower part of the enoki mushroom stems. Break the enoki and shimeji mushrooms into small clumps. Slice the banana chili on the diagonal into pieces about 1/8-inch thick.
  4. Over a medium-low flame, heat a pot (preferably a stone pot) that holds about 3 cups and add the sesame oil. Add the chopped onion and garlic and cook until the onion starts to soften, stirring frequently. Sprinkle the chili flakes into the pot and stir constantly for about 30 seconds.
  5. Remove the mushroom stems and yuksu/dashi bag from the soaking liquid and pour 1 cup into the pot, then add the doenjang. Bring to the boil, stirring often, making sure the doenjang is dissolved. Add the sliced shiitake mushroom caps, tofu and zucchini and simmer until the squash starts to soften. Stir in the shimeji mushrooms and banana chili and simmer for about two minutes. Add the enoki mushrooms and simmer until they start to soften.
  6. Crack the egg into a small dish. Move the ingredients in the pot to the sides to create a deep crater and slide in the egg, making sure to not break the yolk. Simmer for a few minutes until the egg is softly set.
  7. Mince the spring onion and, when the egg is cooked, scatter it over the ingredients. Serve immediately with steamed rice and banchan.

Makes 1 serving.

Source: SCMP

In Pictures: Vegan Roasts

Soft Drinks Affect Women’s Bone Health

Tim Newman wrote . . . . . . . . .

Osteoarthritis, which is characterized by progressively weak and brittle bones, predominantly affects older adults.

As Western populations age, therefore, the incidence of osteoporosis rises in step.

The condition affects around 200 million people worldwide. As a person’s bone mineral density becomes reduced, the risk of fractures increases.

In fact, according to the authors of the most recent study paper, globally, an osteoporotic fracture occurs every 3 seconds.

Although some of the primary risk factors for osteoporosis are unalterable, such as age and sex, some lifestyle habits also play a part.

For instance, alcohol consumption and tobacco use both increase the risk. Nutrition may also play a role, with researchers particularly interested in calcium intake.

One recent study in the journal Menopause focused on the impact of consuming soft drinks.

Why soda?

A number of older studies have observed a link between consuming soft drinks and reduced bone mineral density in teenage girlsTrusted Source and young womenTrusted Source.

However, other studies that specifically looked for an association between soda and osteoporosis have not identifiedTrusted Source a significant relationship. One study found linksTrusted Source between cola intake and osteoporosis but did not see the same effect in relation to other sodas.

Because of these discrepancies, the authors of the latest paper set out to study the links between soft drinks and bone mineral density in the spine and hip. They also looked for a relationship between soda intake and the risk of hip fracture over a 16 year follow-up period.

To investigate, the scientists took data from the Women’s Health Initiative. This is an ongoing national study that involves 161,808 postmenopausal women. For the new analysis, the researchers used data from 72,342 of these participants.

As part of the study, the participants provided detailed health information and questionnaire data outlining lifestyle factors, including diet. Importantly, the diet questionnaire included questions about their intakes of caffeinated and caffeine-free soft drinks.

What did they find?

During their analysis, the scientists accounted for a range of variables with the potential to impact the results, including age, ethnicity, education level, family income, body mass index (BMI), use of hormonal therapy and oral contraceptives, coffee intake, and history of falls.

As expected, they did observe a relationship between soda consumption and osteoporosis-related injury. The authors write:

“For total soda consumption, both minimally and fully adjusted survival models showed a 26% increased risk of hip fracture among women who drank on average 14 servings per week or more compared with no servings.”

The researchers explain that the association was only statistically significant for caffeine-free sodas, which produced a 32% increase in risk. Although the pattern was similar for caffeinated sodas, it did not reach statistical significance.

For clarity, the percentages above display relative risk, not absolute risk.

The study authors reiterate that the significant link was only present when comparing the women who drank the most soda — at least two drinks per day — with those who drank none. This, they explain, suggests “a threshold effect rather than a dose-response relationship.”

It is also worth noting that the scientists found no links between soda consumption and bone mineral density.

Limitations and theories

As mentioned above, earlier research looking for connections between soda and osteoporosis produced conflicting results. Although this study benefits from a large sample size, detailed information, and a long follow-up period, we cannot consider its results definitive; there is too much conflicting information.

There are also certain limitations to the study. For instance, as the researchers note, the participants only reported soda consumption early in the study. People’s dietary habits can change significantly over time, and the team could not account for this.

Also, although the researchers controlled for a wide range of factors, there is always the chance that an unmeasured factor played a part in this association.

That said, when we look at studies involving other age groups, as well as studies using both men and women, it does seem that soda consumption overall might influence bone health in some way.

The study authors believe that this might be because added sugars have a “negative impact on mineral homeostasis and calcium balance.”

Another theory the authors outline concerns carbonation, which is the process of dissolving carbon dioxide in water. “It results in the formation of carbonic acid that might alter gastric acidity and, consequently, nutrient absorption.”

However, they are quick to explain that “[w]hether this factor plays a role in these findings is yet to be explored.”

Because osteoporosis is becoming more prevalent, research into nutritional risk factors is more critical than ever. The authors call for more work.

Source: Medical News Today

Home Urine Test for Prostate Cancer Could Revolutionise Diagnosis

A simple urine test under development for prostate cancer detection can now use urine samples collected at home – according to new research from University of East Anglia and the Norfolk and Norwich University Hospital.

Scientists pioneered the test which diagnoses aggressive prostate cancer and predicts whether patients will require treatment up to five years earlier than standard clinical methods.

Their latest study shows how the ‘PUR’ test (Prostate Urine Risk) could be performed on samples collected at home, so men don’t have to come into the clinic to provide a urine sample – or have to undergo an uncomfortable rectal examination.

This is an important step forward, because the first urination of the day provides biomarker levels from the prostate that are much higher and more consistent. And the research team hope that the introduction of the ‘At-Home Collection Kit’ could revolutionise diagnosis of the disease.

Lead researcher Dr Jeremy Clark, from UEA’s Norwich Medical School, said: “Prostate cancer is the most common cancer in men in the UK. It usually develops slowly and the majority of cancers will not require treatment in a man’s lifetime. However, doctors struggle to predict which tumours will become aggressive, making it hard to decide on treatment for many men.

“The most commonly used tests for prostate cancer include blood tests, a physical examination known as a digital rectal examination (DRE), an MRI scan or a biopsy.

“We developed the PUR test, which looks at gene expression in urine samples and provides vital information about whether a cancer is aggressive or ‘low risk’.

“Because the prostate is constantly secreting, the collection of urine from men’s first urination of the day means that the biomarker levels from the prostate are much higher and more consistent, so this is a great improvement.

“Being able to simply provide a urine sample at home and post a sample off for analysis could really revolutionise diagnosis.

“It means that men would not have to undergo a digital rectal examination, so it would be much less stressful and should result in a lot more patients being tested.”

The research team provided 14 participants with an At Home Collection Kit, and instructions. They then compared the results of their home urine samples, taken first thing in the morning, with samples collected after a digital rectal examination.

“We found that the urine samples taken at home showed the biomarkers for prostate cancer much more clearly than after a rectal examination. And feedback from the participants showed that the at home test was preferable.

“Using our At Home test could in future revolutionise how those on ‘active surveillance’ are monitored for disease progression, with men only having to visit the clinic for a positive urine result. This is in contrast to the current situation where men are recalled to the clinic every six to 12 months for painful and expensive biopsies.

“Because the PUR test accurately predicts aggressive prostate cancer, and predicts whether patients will require treatment up to five years earlier than standard clinical methods – it means that a negative test could enable men to only be retested every two to three years, relieving stress to the patient and reducing hospital workload.”

The Norfolk and Norwich University Hospital receives more than 800 referrals a year to investigate and treat potential prostate cancers. Prostate cancer usually develops slowly and the majority of cancers will not require treatment in a man’s lifetime.

Robert Mills, Consultant Surgeon in Urology at the Norfolk and Norwich University Hospital, said: “This is a very exciting development as this test gives us the possibility of differentiating those who do from those who do not have prostate cancer so avoiding putting a lot of men through unnecessary investigations.

“When we do diagnose prostate cancer, the urine test has the potential to differentiate those who need to have treatment from those who do not need treatment, which would be invaluable. These patients go on to an active surveillance programme following the diagnosis which may involve repeat biopsies and MRI scans which is quite intrusive. This urine test has the potential to tell us whether we needed to intervene with these patients.”

The research team say that their findings could also help pioneer the development of home-collection tests for bladder or kidney cancer.

‘Methodology for the At-Home Collection of Urine Samples for Prostate Cancer Detection’ is published in the journal BioTechniques.

Source : University of East Anglia


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